I don't know if the following situation is common among you, but at my place it happens pretty much with some annoying cousins.
When you're playing and you have to interrupt to do whatever you have to do, you pause the game, and when you get back someone else is playing. Your son is accidentally buying stuff on marketplace. Your dog is playing. Screwing your points. Deleting your progress.
Now imagine a Natal app running in the background, constantly scanning your face. When you leave, the console pauses. When you get back in front of the camera it continues.
If someone else tries to get the machine working, they won't be able because the facial scan will fail.
This app could be used for system startup also. Only you could boot up the console. Also simple gestures would be shortcuts to menus, wave your hand to open the disc tray without browsing the menu for example.
All this while playing regularly on the system.
Do you think is would be useful at a fair price? Or even be standart with it maybe?
Essay Pro