Not only thread locking, but thread trashing.
Actually, yeah. If you continually trash pointless threads, then bounty hunters will eventually stop posting in them. After all, they'll learn their lesson when the post count drops by 100 all of a sudden.
I suggested locking as opposed to trashing since it would be a less radical change however considering the fact that plenty of megathreads
were trashed in past, I don't think there should be much of a problem there.
Every time I go into any board outside of Reputation and Scam Accusations, I see many lengthy threads worthy of removal.