Yea, but people who often cheats on the same game that you play will never say things that will compromise his own game play.
Perhaps, the guy who replied you about if "that player" was indeed cheating can be hired as your referee or special detection group in your tournament.
But then again, there's no perfect utility in order to achieve a "fair play" un-official tournament when the event is held via Internet. Its a different story if the event is held locally in your community (say live Tournament in your place, etc...) then that guarantees a Cheat-Free tournament.
I kinda sound like talking in a loop, so just try to understand what Im trying to say.