Mitch Wagner's written a good piece for Security Pipeline about the danger to the labels if DRM works the way they want it to:
DRM is invisible only when users only want to use data in ways foreseen by the publishers.
DRM makes it harder for consumers to invent their own ways of using technology. A user wishing to listen to digital content on a new type of device needs to go to the media companies first, and ask, "Mommy, may I?"