Yep, just turns off so you can only access "xm preview". Then they start sending you renewal offers. The lowest I've gotten is 5 months for $20. And I think its $60 for the year, but when they first send you offers it'll be more than a $100 for the year.
I've never been called, just sent paper mail. Eventually I'd like to re-subscribe. I'd rock out to the 50's station from time to time, and they had some decent techno and other stations. But yeah, when I got all retro cruiser feeling, I'd be blasting some swingin' 50's music haha.