Some sparrow games are not the full version... Review versions. So they are a huge mark on your console if you have played it online or offline, because as soon as you get online, they update the logs with your play history.

Even there are conspiracies that said, microsoft themselves put the COD5 and Gears sparrow up for download so they can bait modders in using them and efficiently know who to ban.

Assumptions I guess...

And unmodding your console will not help at all. It's marked for death. Sooner or Later.