The gamesmanship or cheaters thread brings a thought to mind. Get a copy of the rules and The Code and have it in your bag. When questionable things are done, stop play and talk to your opponent. Pull out your rule book (cheaters HATE this) and point out the appropriate rule. The nastier or more impatient they are, the longer it will take you to find the rule and drone it out to them for "their benefit." If they do not want to stop to make a fair determination of events by using the rule book, it becomes manifest that they are not interested in fair play and the rules. Then, instead of quitting in frustration as so many do (cheaters count on this) and letting them claim you defaulted, do something else. Disqualify them if they refuse to co-operate with using the rule book if there is no official to call upon. If you are in a league or tourny, notify the powers-that-be that your opponent refused to follow the rules. I have driven some cheaters up the wall by doing this.