Here is another (the millionth) idea how to handle multis/metas, with less moderator involment.
My idea is, just as Muting, every player could have a personal "banlist", where he can switch specific users on/off, marking those whom you don't want to play with. It could work as simple as muting, when you create your own list. BUT!
When you try to join a game, you can join only those where you are NOT on the banlist of any of the already joined players. If you join, then none of those players will be able to join, who are on your banlist. So if you create a game, any type, it would be guaranteed you won't play with those you don't want to. Also it would be guaranteed, when you join any other games.
With this solution the "community" would filter out multis/metas/assholes without using moderator/admin resources.
Opinions?