You have not heard of this I guess, but it's been happening for decades. Here is an American news source for you.
http://www.nytimes.com/1993/12/20/world/americans-filching-free-health-care-in-canada.html?pagewanted=all
Just some highlights. In a 6 month period 60,000 people with American ID got health care paid for by the universal system in Ontario. In 1993 the population of Ontario was 10 million. Health Care cards issued totalled 10.5 million. Who had the extra half a million? Freeloading Americans.