Had a sponsor associated with 1000+ galleries in TGPX & that I wanted to delete. Because I know about the "Deleting a category will also delete all of the galleries contained in that category!" thing, I looked at the Sponsors page in the documentation (admin/docs/sponsors.html):
Nothing. Perfect
So I delete the sponsor......
IT FUCKING DELETED ALL THE GALLERIES
So it's a little over 1900 galleries I've inadvertently deleted in the last 24 hours