While I have, for the moment, decided to continue my subscription, I have put it on a "throwaway" credit card number that my Visa provider supports. On their web site I can create numbers that have a separate expiration and credit line, but bill against the "real" number. At any time I can just turn it off without effecting my "real" account. This usage is one of the advertised points for the feature. If you try to use this feature to "stiff" a company for legitimate charges, they can still go after your with collections, but I don't think that that would be an issue with Sirius/XM.