I'm not too sure any country looks too kindly on people overstaying visas. The problem in the US is for years the enforcement was a total joke. Canada was never so lax in the first place. I know a couple who were given the bums rush from Canada for visa violations and told not to return anytime soon. This was in the 80's.
Flying a lot about following the rules. Seems your friends are not off to a good start.
20driver