@ various
Perhaps 1000-2000 is a little bit low for my idea
Yes, the no bans proviso would be a good one
@ Demoki - a person with 5000 posts and no bans is most likely responsible. They also have a lot more to lose if their account gets permabanned. Obviously there needs to be some post count limit for this to work, because otherwise people with a 0 post count would just come in and ban everyone they could
@ shams, that is a good idea, but if that can only be done to individual posts, then a spammer could post such things faster then they could be blocked. Perhaps our ideas could be combined. Put a thumbs down button on everyone's profile, that you can only access if you have a high post count, and if a user gets enough thumbs down then they get a 1 day block. That way a single person cannot inflict mischief.