I see this as pretty much a confirmation of no anti-used games policy. Why would they anger the place where they get probably a third of their sales from? If Gamestop isn't selling your console; then you pretty much lost the generation.
Here's how I see it going down if the mandatory installs are true (which I now hope they are)
They would be having mandatory installs (which would go along with the HDD and Kinect with every Xbox) so that developers can make their game with those aids in mind which means better optimization for games.
I see the mandatory installs working two ways. The first is exactly like the 360 where you install it to your HDD but you have to have the disk in the tray for the game to work. Once you sell it it won't work anymore. The second way is you install it on your HDD and you pick the option for the Xbox to register that game to your Xbox Live Gamertag (most likely via watermark on the disk). That disk then becomes irrelevant and will not work on any other console that doesn't have your account signed in. Doing this would probably also unlock a feature where you can stream the game from any console you are on as long as your Gamertag is signed in.
By doing things that way they can appease gamers, retailers, and publishers all at once.