It hurts all Buffalo teams. But I think the Bills can survive a drop in Canadian fans. Games are weekly and fans can drive further.
Let me take this to an extreme. What happens if foreign NHL (or any league) players start getting hassled at the US border? They are already giving artists on tour a hard time.
This is not the best time to assume ownership of an old arena. As we see with the new stadium, costs are ballooning. Even if they gave him the arena for free it might not be worth it. Not to mention losing a good number of Canadian visitors. Unsettling is a good word to use here.