Originally Posted by yeunganson

I think this is misleading implying Canadian store processing goods in US dollars. It is very clear in Canadian law, you can only use Canadian dollars to pay for goods in Canada. The situation you are talking about is the purchase is in Canadian dollars. The store first give a value added service by doing a currency exchange for you from US dollars to Canadian dollars. Then the main transaction of applying the now converted Canadian dollars to buy the Canadian Tim Horton coffee/donuts. Then the cashier returns Canadian dollars to you and not US dollars.