It has been my experience that both Sirius Canada and XM Canada seem to be doing what Sirius-US and XM-US should have been doing all along. Unfortunatly, they have overpriced their products and that along with CRTC sillyness has driven a lot of Canadian customers to the grey market.
A lot of the radios and stuff in Canada are now cheaper than in the US. That wasn't the case in the beginning but it is now. Take the Starmate 5. It's $99 CAN. Or the Stiletto 2 which comes with a Car Kit for the MSRP of $299 CAN. Those are better deals than here. Their Boomboxes are more expensive. The pricing structure is just different I guess which like you say encourages people to sometimes buy from the US.