essentially apart from putting a game in your drive or using the software that is on your console from when bought or is an update is classified and that is against there terms fo service which you will get banned for.
For doing gamerscore, if your caught they'll usually just reset your gs back to 0. They don't console ban really unless you have like 100k or higher. Also, if you get reset once on an account, and if you get caught again on the same account modding gs, you'll get banned. So just saying if you ever get reset make a new account and do it.