I think it would be awesome if owner's of threads could lock/delete a thread they posted. Such as if a contest was completed, the owner could lock this if they wanted.
I saw an example of this on a pixel art contest, where the thread owner wanted his thread locked, but he had to wait for it.

This would be good because what if someone realized that their forum post was against the rules? Then they could delete it without getting in trouble. Also, this would help for thread owners when their problem is resolved. This would prevent necro posts.

Thanks for reading.