It's not as common as OP made it out to be, but I think some people are downplaying how often it happens. Maybe once a month I play against someone whose CC rating is double their blitz or standard ratings with many games played. They also tend to play very accurately.
I simply do not believe a person who is sub 1000 in live chess can play at a much higher (1800+) level just because they have more time. A low rating in live chess shows a lack of basic positional understanding of any kind, and no amount of time will help them find things they don't understand.
Frustration with Turn-Based Games


Godlike makes a good point. Though extra time and the possibility to move pieces can help a lot, they won't make you find strategies or play technical endgames like a GM.
Besides, the 3 days/move is relative : how many people are really taking hours on every single move, or even have the focus to do it should they have the time in the first place ? For many players, corr. is just a handy way to play their moves when they have time, rather than spend hours moving pieces around...
I simply do not believe a person who is sub 1000 in live chess can play at a much higher (1800+) level just because they have more time. A low rating in live chess shows a lack of basic positional understanding of any kind, and no amount of time will help them find things they don't understand.
These are the kind of statements that we see over and over again from people who think online chess is the same as live chess. It's okay, we all see the world from our own perspective, but live play is not the same game as correspondence.
Let us examine your statements.
"A low rating in live chess shows a lack of basic positional understanding of any kind"
This is the exact opposite opinion of public consensus, the opinions of chess coaches, and the opinions of strong players. It is held as empirical fact that those with low ratings in live chess primarily have the problem that almost all of their games are decided by tactical oversights. Further, I would guess that there are many weak players who have a decent basic positional understanding, but again, they lose games primarily due to tactical oversight. Basic positional understanding is not rocket science. Any 1200 player can learn it here in 17 minutes and 8 seconds:
https://www.youtube.com/watch?v=r2HUcuiSJi0
However, a 1200 live player is spending their time trying to avoid hanging a piece, and there is no way they could apply this simple positional evaluation during live play.
"I simply do not believe a person who is sub 1000 in live chess can play at a much higher (1800+) level just because they have more time"
Why do you believe this, other than it not being the way you understand and play chess? What are the primary problems that a weak OTB player faces? Primarily two things: 1) Tactical oversight, and 2) Lack of time to apply positional or strategic thinking. Correspondence chess solves both of these.
To solve the tactical problems faced by a weak player, simply enumerating all of the forcing moves, and then going one move beyond, will keep you safe in the vast majority of positions. There will still be deeper combinations that a computer or stronger player could find to defeat you, but at 1800, this approach effectively solves the problem of tactical oversight.
To solve the positional and strategic problems faced by a weak player, a player can adopt any number of prescriptive thinking systems, combined with some of their own study. There are numerous methods that are more than sufficient to reach 1800. Here are a few, pick any of them:
- How to Reasses Your Chess
- Find the Right Plan with Anatoly Karpov
- The Process of Decision Making In Chess
- Use the positional evaluation video (above) by IM Martin, calculate forcing moves, then apply his simple method.
Further, it is quite obvious that most online correspondence players do not play any differently than they would play a blitz game. They use online chess as a way to play when they have time. There is nothing wrong with that at all. But that dynamic means that a player who does spend extra time to analyze their options will greatly increase their advantage. Excluding beginner players who do not yet have the experience to absorb chess ideas, and excluding massive rating differences (GM vs 1400, etc), time spent is going to be the most important factor in the majority of correspondence games. An 1800 blitz player who spends 10 seconds on his correspondence move is just going to lose to a 1300 blitz player who spends 2 hours on his move.
Further still, many OTB players, especially at faster time controls, use the strategy of complication to great effect. They complicate the position in their pet opening, and with only a few minutes on the clock, the dubious-but-aggressive approach will score many wins. Many strategies of practicality are completely ineffective in correspondence games.
I think most OTB players only view correspondence chess through their OTB lens. They somehow get offended at the idea that a weak OTB player beat them, and the easy assumption is they are cheating. No doubt some are cheating or half-cheating. But there is much more to the story with correspondence games. The OTB player who thinks "chess is chess" loses some of his advantages. The correspondence player gains many advantages. There are many shifts in advantage that tilt the scales in ways that are not always obvious.
Saying that there is no way weak OTB players can perform well in correspondence is short-sighted. It's like saying Bruce Lee could never be defeated by a poor fighter. That is true if we are talking about a street fight. But change the game, with Bruce Lee facing a dozen police officers with guns, and Bruce Lee loses.
OTB chess is its own skill, just as correspondence chess is its own skill. Why should anyone find it strange that when OTB players start using correspondence games as a mechanism for their own convenience, the players skilled in OTB play lose to the players skilled in correspondence play? OTB play and correspondence are more different than people think. One is a real-time adversarial competition, the other is a research project.

Godlike makes a good point. Though extra time and the possibility to move pieces can help a lot, they won't make you find strategies or play technical endgames like a GM.
Besides, the 3 days/move is relative : how many people are really taking hours on every single move, or even have the focus to do it should they have the time in the first place ? For many players, corr. is just a handy way to play their moves when they have time, rather than spend hours moving pieces around...
This was my point: the people I was playing (I am only talking about two, one who I think used an engine for every move, and one who used one selectively) snap-played their moves.

The idea that anyone can find the best move if only they have enough time is just nonsense... I don't care if a 900 spends a whole week on every move, he will still play poor moves.
Online chess is pretty much a waste of time in a competitive sense, it's rife with cheaters. It's not without value though. Personally I use it as a bunch of separate problems to solve each day. I try to find the right tactic or plan, quickly, then move onto the next game.

It's not without value though. Personally I use it as a bunch of separate problems to solve each day.
After I became frustrated, I began playing way more games to give myself more positions with just your reasoning. I was only playing a couple and thinking about the games thoroughly throughout the day previously, only playing 3 games at a time. I figure that since my day-long thinks are being met by crushing snap-played moves by someone at least 500 USCF points lower than myself, I might as well use the turn-based games for a different reason.

It's not without value though. Personally I use it as a bunch of separate problems to solve each day.
After I became frustrated, I began playing way more games to give myself more positions with just your reasoning. I was only playing a couple and thinking about the games thoroughly throughout the day previously, only playing 3 games at a time. I figure that since my day-long thinks are being met by crushing snap-played moves by someone at least 500 USCF points lower than myself, I might as well use the turn-based games for a different reason.
You can always slow down and analyse in-depth when you come to an interesting position or one that's relevant to your other studies.
It's worth bearing in mind that ICCF came to the conclusion that preventing engine use was impossible so simply allow it in their games. For Online chess, the same applies - it can't be stopped.

The idea that anyone can find the best move if only they have enough time is just nonsense... I don't care if a 900 spends a whole week on every move, he will still play poor moves.
Online chess is pretty much a waste of time in a competitive sense, it's rife with cheaters. It's not without value though. Personally I use it as a bunch of separate problems to solve each day. I try to find the right tactic or plan, quickly, then move onto the next game.
I think this is right. Every now and again, I'll get blown off the board by a lower rated player and it's suspicious but I'm damned if I know how to stop that problem. Play a bunch of turn based games, use it as a problem-solver and save the competitive fire for OTB in the tournament halls.

The idea that anyone can find the best move if only they have enough time is just nonsense... I don't care if a 900 spends a whole week on every move, he will still play poor moves.
Online chess is pretty much a waste of time in a competitive sense, it's rife with cheaters. It's not without value though. Personally I use it as a bunch of separate problems to solve each day. I try to find the right tactic or plan, quickly, then move onto the next game.
I think this is right. Every now and again, I'll get blown off the board by a lower rated player and it's suspicious but I'm damned if I know how to stop that problem. Play a bunch of turn based games, use it as a problem-solver and save the competitive fire for OTB in the tournament halls.
I think we're coming to a pretty solid consensus.

It's worth bearing in mind that ICCF came to the conclusion that preventing engine use was impossible so simply allow it in their games. For Online chess, the same applies - it can't be stopped.
It can't be stopped in advance but the damage can be limited by post analysis and reporting. May not get 100% coverage but it sure is a heck of a lot better than just allowing it.

Reporting it doesn't do any good ... I've tried.
Reporting can do good; a lot of accounts get closed. There may be a high burden but not reporting isn't a solution.

You kinda have to figure though, that anyone using an engine is gonna drive their score up 2000+ in just a few games. It's the nature of the beast. Sorta like if a magic genie told you that you could have all the money in the world, but, you only took 300,000$ That's just not how it works.
If a player rated say 1750 plays a 1950 and blows them away, if the 1750 is using an engine, he'll be 2000+ in just a few more games. However, if the same 1750 plays 35 more games, and is still only rated around 1800 he isn't using an engine.

People take many different approaches to online chess. It's always easy to just think someone is cheating and if you let yourself start thinking that you can start thinking it of too many players. I've been in plenty of (online) tournaments where I see that someone's account got close mid-tournament for cheating. It's frustrating if they played and beat me twice, but were still mid-game with some other players who got points by default, but it isn't regular enough to really bother me and I don't take too much notice of my tournament position usually. Just occasionally I realise one or other game could make a difference between me qualifying or not.
I am very inconsistent in my online games though. The thing with online games is they are always there unless you take a hard break and finish them all off. I've had 20-30 games (sometimes more) active continuously since I joined chess.com. Some days/weeks I just really don't feel in the mood for chess so I just go through the motions and make a quick move. In fact in most online games I am making moves ony when I have 24 hours or less left as the trigger for me to move, irrespective of the time control.
Then occasionally there is a game that really fascinates me. I may make quick moves in 10 other games then spend an hour and a half on the analysis board before moving in this one game. Some chess games are exciting, plenty are not...it affects the amount of effort people put in.
For some having more time available or an analysis board makes a big difference in thir play quality. I'm usually lazy so it doesn't make a big difference in mine which is why my ratings are similar across most time controls.

@vyik
I'm not trying to give a guideline for 'identifying' cheaters, as much as one for 'feeling content' that a player is not cheating.
As I've stated a few times, I've recently learned that players who only play online chess(correspondence) have a tendacy to bust out some pretty SOLID combinations(almost like they used an engine). Vs a player who is mostly only an OTB/blitz player, these players tend to be more inclined to 'take risks' that capitalize on time pressure.
There is ZERO 'rhythm'(time manipulation) to correspondence chess, it is 100% calculation and execution. A game can start out a lot like a regular timed game, but then once a player has three days to look at a move/position, if the player uses this time wisely, well, he's gonna look pretty good on that one particular move.

You kinda have to figure though, that anyone using an engine is gonna drive their score up 2000+ in just a few games. It's the nature of the beast. Sorta like if a magic genie told you that you could have all the money in the world, but, you only took 300,000$ That's just not how it works.
If a player rated say 1750 plays a 1950 and blows them away, if the 1750 is using an engine, he'll be 2000+ in just a few more games. However, if the same 1750 plays 35 more games, and is still only rated around 1800 he isn't using an engine.
...if he uses an engine all the time. There may be many reasons why a player uses an engine only selectively :
- to avoid detection (esp. if has been already banned)
- part of a personal routine ("one game I play with engine to learn, one game without to practice")
- blunder-checking only ("I make the grand plan, the engine prompts me if I drop a piece")
- to get some personal revenge ("hey you beat me 6-0 OTB, I'll show you who's the boss" or "ah this dude is a famous player/cheat hunter/coach, let's blow his head
"

You kinda have to figure though, that anyone using an engine is gonna drive their score up 2000+ in just a few games. It's the nature of the beast. Sorta like if a magic genie told you that you could have all the money in the world, but, you only took 300,000$ That's just not how it works.
If a player rated say 1750 plays a 1950 and blows them away, if the 1750 is using an engine, he'll be 2000+ in just a few more games. However, if the same 1750 plays 35 more games, and is still only rated around 1800 he isn't using an engine.
...if he uses an engine all the time. There may be many reasons why a player uses an engine only selectively :
to avoid detection (esp. if has been already banned) part of a personal routine ("one game I play with engine to learn, one game without to practice") blunder-checking only ("I make the grand plan, the engine prompts me if I drop a piece") to get some personal revenge ("hey you beat me 6-0 OTB, I'll show you who's the boss" or "ah this dude is a famous player/cheat hunter/coach, let's blow his head "
I mostly play correspondence and have a significantly higher rating in CC than I do in any live catagory. In CC I will take huge amounts of time, I will use the board to analyze each candidate move 5, 10, 15 or more moves deep. I will jot down notes ruiling some candidate moves out while marking others as a strong possibility. I will look at openings, I will study other games in a similar position, I will read articles, I will use every tool that Chess.com allows in order to make the strongest possible move I can.
All of this goes out the window when I play live and have to think on my feet. I usually fail miserably.
Chess fascinates me, and at this point in time my interest is more in analyzing, researching, as one user put it, the board, the position and trying to work out its puzzles than in banging out moves on a whim.
Also, OP, don't assume that just because someone slams out a move quickly after yours that they're necessarily using an engine. They can still study the board while it's your turn. While you're working out your next move, they may well be too.
Don't allow yourself to fall in to this trap of thinking that just because someone appears to be playing outside of their rating that they are cheating. There are many much more likely reasons why this could be other than cheating.
Really, that type of thinking is a disease. Once it starts, you are going to start seeing cheaters around every corner.
I've played about 3 times as many games as you and I've never encountered a cheater.
I think i have a good example of that disease you are talking about, look for LullabyVista comments in those links:
http://www.chess.com/groups/team_match?id=478566
http://www.chess.com/groups/team_match?id=454562
http://www.chess.com/groups/team_match?id=509396
http://www.chess.com/tournament/the-swashbuckling-evans-gambit
http://www.chess.com/tournament/open-catalan-2014
http://www.chess.com/groups/team_match?id=443918
http://www.chess.com/groups/team_match?id=514856