How do you know of you're playing a cheater?

[The site's policy is to limit discussion about cheating to the Cheating Forum. http://www.chess.com/groups/view/cheating-forum. More information in the FAQ http://support.chess.com/Knowledgebase/Article/View/124/0/cheaters--cheating-what-you-need-to-know. Moderator]
When a person with a lesser rate win me.
not at all.