@Ivo - I don't mean cancel every game with a cheat in it no.
However, as V says, lots of people take more pride in their %ages than points. If a game is wrecked by a cheat, and we catch it in time, we can cancel it. However once its finished that's it: it'll go on their profile and there's nothing we can do.
As for regular players who did well vrs Cheats - yes it gets difficult then. Suppose Russia & Turkey are a multi. They make a good start, but the others realise what's going on, kill them off, and England takes the win. Now, if you were England you would feel this result should stand, but how about Austria? For him, the game starts with his neighbours wiping him out, and he would have had no chance of escaping it.
Are these acceptable? http://webdiplomacy.net/rules.php
I would like to see each rule title made into an anchor, so we could link players directly to the right rule (ie as http://webdiplomacy.net/rules.php#metagaming) but apart from that seems ok to me. The only other thing is that it could do with being renamed - lots of people assume 'rules' means 'rules of diplomacy' not 'site rules'