its quite possible they would use it as said here in an interview with harold ryan
http://news.teamxbox.com/xbox/20080/Bungie-Halo-Reach-Could-U se-Project-Natal/ (im a bit new so im still learning so no link :( )
i think it could be cool aslong as it wasnt like the wii id even go far enough to say that project natal could enhance the xbox experience
but i agree i dont want it in reach untill i see it at work