@Nivix You don't grant the users actual power. Someone from YouTube said the same thing. (Can't find it where he said it though, probably in one of his livestreams) But the way to do this is to setup some clear guidelines on how you want your users to behave, Let the users engage the user in question without harassing him. Thats basically the whole trick. Adjusting is easier if the whole group communicates in the same way.
