Flash hacking is also possible in bullet games...I have had it happened to me...

These days, you can't even fart without someone detecting it.

I agree with both of you 100%. But, in terms of prevelance, bullet has to be the most trustable.

How do you figure? You think bullet players are less likely to want to cheat?

Especially with the opening research you must do, the openings tip you off I bet.

I had prepared this little known line for tournament play once, and after playing like a beginner, the next game my opponent suddenly happens to know this odd line 10+ moves deep... lol.  I wonder if these types even know how obvious it is.

While you are most likely right, I do think it is possibly for a player to play like a newbie, if they aren't really strong but, if they have taken the time to try learning something intricate (perhaps by chance) and in depth, that you aren't familiar with, it could catch you a bit off guard.  

I  have played a guy I work with the last two days at lunch, OTB. I ground him to bits in a QGD, using the Slav, in our 1st game. I was certain he was decent but, I was a notch or two above, considering I hadn't played him with white yet, where I am more familiar with the Ruy Lopez and how to deal with the Sicilian, more so than I am familiar with the Slav. He played the Elephant Gambit against me. I have maybe played against it once or twice, so long ago, I remembered next to nothing about the positions. He proceeded to dismantle me, worse than I had beatenn him with the Slav.

We started another game that we couldn't finish, he with black having chosen the Scandinavian Defense, it is almost a dead draw in the early middle game, with no queens on the board. I have had a few people surprise me here also...

Hey, what a novel idea; playing face to face in a real place.

Why nobody thought of that before?

you're talking about obvious cheating which can easily be busted by some statistical analysis. (that's also why cheating is less common in bullet. besides just being harder, it's glaringly obvious and very easily busted in review)

my question is, what if an actually decent player goes centaur mode? in standard or correspondence time, there's lots of time to do even relatively harmless things like "blunder check" (make your move, and if your score drops significantly then you obviously made a blunder and should pick something else), or in a worse case feed lots of plans and try out some plausible continuations with the engine, etc...

this isn't something that even is exclusive to online chess. let's say that two GMs are playing and they reach a very sharp position... the only thing a GM needs to know is "does this move work or not" and so he could go to "the bathroom" to check the position on his pocket stockfish or something, or have an "assistant" do it, or whatever.

i'm obviously not the first person to have that kind of concern, and most recent tournament rules at the top do try to prevent these things from happening. anyway, the point is, the better player you are the less obvious your cheating can be, and that greatly worries me regarding online play at slow/correspondence time controls because i think that it could be pretty much undetectable.

This is not cheating. If you played a certain line and your opponent lost and then went off someplace and analyzed the game with a computer, this is within the rules. It is only against the rules if the opponent uses the computer while actually playing. 

I play in a chess club in the public library. If we have to play nude wouldn't it be distracting for the old ladies who just came in to read?

How can people think they can detect engine use?

By the smoke from the exhaust.

I remember a while back someone thought of this joke where he tells his opponent he thinks they use an engine. He gets them all worked-up then says 'If you don't use an engine, how do you drive to the market?'

I would agree with paul. I think for most people setting up a program to play your moves for you is considerably more difficult than the traditional (too soon to call it this?) engine forms of cheating.

On topic, occasionally in standard or online you will play against someone who plays with such overpowering accuracy that it seems obvious they are using an engine. 

Blunder checking isn't in any way harmless...it is like rolling a snowball down a mountain side, above town, after a heavy snow...

...I figured out how to catch people blunder checking though 

Each position has an inherent difficulty, in finding the best move. If you have to check for a blunder, that generally means you are getting in over your head, from a skill stand point. If you understand the position, you'll know if you are blundering when you move, unless you wittlessly are shoving pieces, such as in bullet or blitz.

When you use your own skills to make your moves and then later seek the aid of a computer, after it gets  too hard, it begins to affect the performance ratio between position solving difficulty and moves chosen. If you think meddling with choosing moves, having a lower eval score can circumvent this detection, think again. It also can catch it too.

There should be a steady drop off in performance as skill level requirements for positions increase. If it is inconsistent, naughty, naughty.

Not only can using this be effective in comparing you to yourself, you can also be compared to other players, who are known to be reliably rated and honest. This is far more exstensive and reliable than t-3/4 standard deviation check methodology.

that seems cute but i dont see how "skill level requirements for positions" is measurable, or even "performance". i mean, you cant really say "to find the right plan here you must be at least 2000 ELO" or "the move 15 Ng5 is about 1600 ELO", can you?

(Edited for clarity)

I do understand how to measure it...

it has nothing to do with finding the right plan, or using Elo ( an estimate, based on other estimates, always in flux and at best, another estimate)

Each chess position requires a particular amount of skill to find the best move in. You could possess that skill but, have any number of different ratings, based on various factors. People get confused between the effort it takes to solve a position and the skill level it takes.

An example anology... A 200lb man might have to give it a 100% effort to dead lift 500lbs but a 300lb man might only need to exert 75% of the force he is capable of exerting. In either case, it still takes over 500lbs of force to over come gravity...

i was just imagining some kind of crazy example because i guess i don't even get what you are doing

Reread my above post. I clarified some things...

so how could you use that to catch people if you don't know their skillsets and how much effort they are putting in... or how do you even determine how difficult a position is

This straight up just makes no sense whatsoever. It assumes that each chess position has some kind of requisite skill level in order to solve it. This of course is a trivialization and oversimplification of the myriad different factors that go into chess play and decisions.