I'm fairly certain it's because youtube users are privy to their traffic sources, and will delete their own videos if they see where they're ending up. It started happening with a lot of mainstream stuff, I think that's why we started doing it. Youtube videos end up on a lot worse sites than this, and stay up. I doubt TMF drives anywhere near enough traffic for a red-flag, and even if it does, most of these videos do not conflict with Youtube TOS.