Is it possible to know if someone is cheating in correspondence chess? Consider a mobile chess app which allows to play correspondence chess.
Some apps, like this one, state that they'll punish someone (e.g., disable their account) if they discover that the person is cheating.
Is it really possible to reliably know if someone is cheating (e.g., uses a chess engine to decide on the next move)?
Are there any heuristics that can exist in the app that will calculate the probability that a player is cheating?
The answer is, "Yes." See this article:

http://www.uschess.org/content/view/12677/763

Does your phone application have this capability? Probably no... yes! So don't do it!