It's been Damo's policy that the mods can thread ban upon request. They don't want it used unnecessarily/without cause, though, so, we probably won't get that option. If there's someone you genuinely dislike, you need to ban them the first time, otherwise your request will be regarded as trolling.
Edit: I remember Grind stating that they would stop doing this over a year ago because it was becoming a problem.
Bookmarks