also, let's look at this from another point of view. what's the point of buying single player games, if all i have to do is wait for one of my xbox live buddies to get bored of it? I'd think this would hurt the industry more than used sales. it'd also force devs to always shoe-horn in some type of multiplayer component, even for campaigns.
All they would do is put a limit on how long you can borrow it just like Blockbuster did so many years ago. They can DRM the DRM all they like once they fully implement this system.