Ask again for new page, seriously curious. Thread is blazing though lol.
Don't know why they don't just do that. When you decide to sell a physical disc you go through the same process you would do if it was digital. Go to your console and mark your game as "selling" at which point it will become deactivated on your console and account. It will connect to the internet to confirm this. Then you take the disc to gamestop and they buy it from you and check if the game has been deactivated on your account. If it has then they will buy it, if not they will ask you to go deactivate it. Considering that the console has to connect to the internet to install and activate a game anyways I see no problem with continuing this process for removing a game.