They're supposedly "tamper proof" stickers. They're not supposed to just come off.
I personally don't think they were ever put on by Vandy, and I said that last night. I think it was "gamesmanship" on behalf of Corbin. TV said multiple times, "I've never heard of stickers coming off, but somehow we managed to have 3 more bats without new stickers." And he said all the bats were inspected by Vandy on Thursday.
What would provoke the catcher to inspect the sticker after a huge hit like that? And there's been series with Vandy where Corbin, iirc, has requested multiple bat checks.