Depending on how important this is (and how much you want to spend), you could get a Canadian cell phone. Telus Mobility in BC has a $25 per month "Your Choice" plan. Or, get a prepaid phone and buy $10 or $25 cards. That doesn't help if you have the box connected to your land line, of course. However, you could order PPV manually over the cell phone. It's possible that the phone system will still know that you're in the USA, but I don't know what kind of routing info (if any) is presented with ANI. For the main "US vs Canada number" question, it's real easy to have a list of prohibited area codes to check against the basic ANI number.
As far as "why are Bell folks being such twits about this?", that's a good question. One would expect that any auditing done by programming providers would be the same for both Bell and Shaw. Likewise, any government restrictions should be the same. Maybe Bell has more restrictions from the programming folks because of some earlier problems? Or, maybe the folks who run Bell simply don't like Americans?