I can't recall where or when I read it, but there was some talk that Kinect might also be used in an office setting. Microsoft may well be thinking about it and having an open source driver going around might cut into their plans they could have for Kinect.
Edit:
Kinect is part of Microsoft’s continuing quest to bring to market natural user interface (NUI) technologies, like touch, voice and gesture-recognition. Maybe it’s also part of a grand plan to force users to continue to exercise (even if that just means by waving a hand) while being increasingly tied to our PCs?
http://www.zdnet.com/blog/microsoft/microsoft-kinect-for-gam...