No one is holding a gun to your head.
Exactly.
Most of the advertisemants shown have to be prompted by you, the user. Most of these ambient advertising methods are useless without an incentive and I doubt anyone's going to want such a useless tool...especially companies like Toyota who'd want to drop a 30,000$ hybrid car like the Prius on such a low income market.
The only useful tool I saw on there was a schedule tool which would be good to remind users not just when TV shows come out but when games, DLC's and 360 exclusive demos are released...and it can be achieved without Kinect.