It's more likely that companies like Bell will pressure the CRTC to make it illegal for Canadians to purchase the service from non-Canadian owned companies, similar to what they did with satellite TV. Internet access is different because, unlike TV content, it's a common carrier that merely facilitates communication, not the resale of copyrighted content. Even that was relaxed for internet services like Netflix. I'm hoping that the CRTC will extend the same philosophy to internet satellite.
While SpaceX internet sales may possibly be restricted in Canada, Canadians are breaking no laws or treaties by subscribing to internet from another country. It will also be very difficult to enforce. The only thing that currently limits internet service sales to Canadians is that the infrastructure has to be located in Canada. The SpaceX satellite constellation changes that physical restriction in a revolutionary way, not just in Canada but worldwide. Unlike existing satellite internet services, the SpaceX constellation has the potential to directly compete with fibre and cable internet in every way.