I reported before how I think it's in pretty bad taste when EA spams you simply for playing their games. Well, it goes a little bit deeper than that. EA has access to all of your Xbox LIVE account information, and that includes your credit card information. Not comfortable? Of course not. They don't seem to have a lot of morals about abusing their access to your information.
Usually with this sort of thing you can just opt-out. Annoying, but you get used to this sort of thing. Not EA though. If they can't email you about whatever they want, you don't get to play their games. Paying for them isn't good enough, they need to be able to annoy you as well. If you opt out of their email system they shut down your access to playing online.
Just keep in mind what you get when you buy an EA game for the Xbox or 360 to play online. You'll be getting servers that aren't nearly as stable as MS's. You'll be signing up for EA's emails with no possibility to opt out. This is how they thank you for your business.