I've noticed some really amazing play out of some folks who have far lower rating than I have.  I know everyone has a good game every now and then.  Not an issue.  But has anyone else encountered people they absolutely knew were using a chess program to assist them?  How do you ever really know?

http://www.chess.com/groups/forum/cheating-forum

Some cheater detection methods are discussed there.

Most people are underrated because they are new and haven't normalized their ratings yet. Unless the people you are talking about just decide to cheat randomly in one game and not another, they are going to have very high ratings.

Yes, I checked number of games played and it was enough (around 700) to normalize a rating. 

The cheating forum was helpful.  I'm not going to report the person since it could be I had a "bad chess day" and he was having an exceptionally good one.  I was just curious if there was a way to detect.