WTF Microsoft. Y U NO REPECT PRIVACY?
So, Microsoft has patented spying on your via your TVs camera. Say you rent a movie via XBox and try to watch it with a bunch of your friends, the Kinect would be able to detect if the number of people watching it is more than how many the license allows, and maybe turn off the movie.
This link has more details. It's more likely a move to please the studios than anything else.