Often spammers, or drunk people who feel the need to post racist/sexist/otherwise offensive content come to the site and post something spammy or offensive.
The good folks of this community usually respond fairly fast by flagging the posts as offensive or spam, and they get deleted soon enough. (Two recent examples, for the 10k users amongst you: spam and offensive posts.)
But the users, usually unregistered, still remain active. True unregistered users are "harmless" in the sense that it's unlikely for them to come back, so often suspensions are of little to no point, but it does make me wonder:
Why aren't users whose only post was destroyed using spam/offensive flags get automatically deleted?
And if there is no automatic purging mechanism for these sort of users, perhaps it's worth implementing one?