A whitelist would make sense, but it definitely wasn't that way a while back. The PS3, Boxee on Apple TV and others were all reporting pretty odd user agents and flash versions that I doubt they had whitelisted. Only once they realized people were *gasp* watching TV shows on their TV did they start cracking down, blocking them based on blacklists. Boxee played a cat and mouse game for a while, until it just became too unusable on the Apple TV.