I don't think it should be disallowed. It has some (small) strategic value, and beats hell of replacements IMO...I might suggest that mods require a
Confirm Vote: self
to avoid the frustration-vote becoming deadly to a game.The other trend I've seen is mafia in newbie games night-killing themselves when they get in an unwinnable situation (Night 2, one mafia dead, cop and doc still alive, for example). I'm not sure how I feel about that either, since it deprives the town of a truly satisfying lynch, but it has its uses, too...