I am Canadian, minority on this site, but we always have out of country extended medical.
primarily it's for travel to the US, we are there often and no Canadian wants to be there without extra medical coverage.
lots of horror stories of Canadians selling houses or being deep in dept over US medical expenses, luckily never have had an occasion to need it so far.
Recently a friend without extra coverage broke her shoulder on arrival at LA airport - racked up a 15k bill at the local Kaiser hospital before she returned on the plane home same day. On return filled that $1100 US pain killer prescription for $15 at the local pharmacy.
on the other hand trips to the ER doctor in Norway NL, Cuba and Thailand cost less than extended coverage.
so much less we haven't bothered with the paper work to collect.
however just paid for the wife's ambulance, MRI, Cat Scan, Xrays, Blood Work, Hospital Stay and Medications after being run over this September in Chartes France
cost 220 Euro and our standard medical will reimburse it.
I've never heard of a different coverage being required for an air evac in Canada but would expect if you cause search and rescue to be activated beyond what would be normally expected some one is probably going to have to pay for it.