So about 2 weeks ago I lost my paypal card, that was being used to pay for my xbox live account. Since I couldn't find my paypal card I ended up canceling the account to prevent theft.
Anyways since my paypal card was canceled, my monthly xbox live subscription couldn't bill me. Right now I'm still able to play CoD mw2 online. The only thing that's happening is xbox live sends me an xbox live message telling me "They are unable to bill my credit card and I need to change the payment method". I just ignore it and continue playing.
Anyways I know this isn't a WoW exploit, but it's still good for those of you that play xbox live.