What Microsoft themselves have confirmed is that games must be installed onto the HDD - this is mandatory. After this, the disc is no longer needed. This casts quite a big "no way" onto this rumour.
If the disc is no longer needed, then I would be free to sell this disc to a company like EB Games (I'm Australian) at which point it would go into their collection of copies.
If the code doesn't update until it's resold and used by a new purchaser, then I could potentially hold onto my game for quite a while afterwards - granting me free access to the game, despite having sold it and used the value to buy a new game.
While this situation then might seem ok, it's also entirely unnecessary to then validate that content.
At current, if I lend my Xbox 360 game to my friend, I can't play it anyway because I no longer have the disc. If I re-sell the game, I can't play either. This rumored new system enables me to continue playing the game after I've sold it until someone else uses it.
Microsoft wouldn't make a new system that grants users this type of access, while requiring them to create 300,000 servers... to do absolutely nothing for them. Literally, Microsoft would see no benefit to this system of any kind.
So, no, don't believe it, sorry. The Always Online internet connection is there for a reason - used game codes, and requiring Microsoft Partners to "de-authenticate" codes creates the necessity, and creates a benefit for Microsoft in doing so: used game profits. This rumoured system does neither.