I have noticed if you sign into MS live ID, it does give you all your info including your address and card details, i never put them in there, but after i first bought MS points, then they appeared there.

So i'm thinking if you delete them out of there, It might be the way to remove the details, which for the short term would stop somebody stealing your xbox and using it to buy or use MS points using your bank or credit card.

Also the 5 year thing is not good either!