I think it would make sense to disable up/downvoting for top-level comments in 'stupid question' threads, actually. This would have the added benefit of attracting conversation from lurkers and 'outsiders', without the danger of having the whole forum go to hell. A little outside opinion would always be welcome.
This is a thread where people can ask questions that they would ordinarily feel embarrassed for not knowing the answer to. The previous "stupid" questions thread went to over 800 comments in two and a half weeks, so I think it's time for a new one.