Can you obtain a "real" US subscription from a Canadian Radio

For those that don't know, Sirius Canada and Sirius USA are separate companies. In Canada, Sirius is very dominant and has a lot more subscribers than XM.

I have heard mixed chatter that you can buy a Canadian Sirius OR XM radio and then have a US sub with it. What's conflicting is whether or not you're getting a Canadian "feed" that is actually the Canadian subscription but you're being charged from the Sirius USA. What I read somewhere is that the software in the radio will look at where the radio was initially designed to work in (country) and then run the appropriate feed.

Neither Sirius Canada or Sirius USA will elaborate on what happens if you take a Canadian radio and try to run a US subscription on it.

Does anyone have any experience?