Found out that the Gamesharing rules & regulations are different on XBOX360. Bungie is not legally bound to game share across multiple acounts, so they haven't... They have just decided to say nothing! Even though the Microsoft Usage Restrictions on 360 states "The item you are trying to download is subject to usage restrictions. You can use this item on the first xbox 360 console you downloaded it to. Access to this item will also be granted to all users on this first console." The only thing you can do is ask for a refund from Microsoft