Speaking on no clarification for Kinect, Microsoft filed a patent that covers it being able to determine how many people are viewing a movie on the console. As it, while your viewing it - Your watching a movie, and it will know how many people are in the room watching it with you. I don't think this extends to playing games or music with it... Yet.
I haven't read anything on this for a while, but apparently them and the mpaa were kicking around the idea of putting limits on how many people you can have in the room with you when your watching a movie. If it detects more then say... 5 people in a room, it won't let you watch a movie and will instead ask you to purchase a lisense for that movie so you'd be able to view it with that number of people in the room.
Ah, here's a newer article about it.