Is it possible to put a one hour or so limit on deletes?
I'll take another look at the settings, but I don't think so. That would be the ideal solution though.
I can allow/deny the ability to delete posts based on the member group someone belongs to. Member groups can be assigned by me or based on the number of posts the user has made. Basing it on the post count is useless because I don't care as much if someone who has only made a few posts deletes them all, it's the people who have made hundreds of posts that do damage by deleting them.
Basing it on assigned member groups means I have to predict who is likely to delete their posts, and I've had people from both sides of the hoax debate delete large numbers of posts.