MS actually makes money on each Kinect sold. See http://www.mcvuk.com/news/41487/Kinect-priced-for-profit

So in theory each Kinect sold for hacking is money in MS's pocket.

Given that MS has bought a slew of patents all around this space, they may be playing coy here.

"Please don't hack this... please don't. Oh drats, you figured out a way around our advanced hack-proof system. But what can you do with it? Nothing probably, you surely can't think of some really cool ideas that we haven't... Oh you can give some additional hints to your Roomba from the couch with hand gestures... go on..."