It's that smug look on their faces. You know the one... 'heh, we've got the tooth and we want to share it with you but your probably not going to listen to us and die while we live forever' look.
In reality it's not much different than the look you see on moonies, scientologists, hari krishna's..., but when you combine that smug look with a book bag; you know it's a dub.