>> The numbers are vanishingly small
Maybe as a % of the overall Canadian population, perhaps. What about the % of critically ill? People with cancer? My aunt is an oncology nurse at one of the best hospitals in the nation, and she sees a lot of Canadians who come to the US for treatment that they can't get at home.
So yes, people with the flu or a broken arm probably aren't flocking here for care. People with serious illnesses? You bet they're coming here.