I for one will not travel without travel insurance. I, too, have Blue Cross Blue Shield Federal Employee Program (excellent insurance) and they do not cover med evac. Also, unless the physician/hospital is participating (which I'd be willing to doubt they are in a foreign country), I am responsible for 20% of the difference in what the fee is and what the insurance will pay. That can really add up.
Insurance for myself and my husband for a standard 7 day cruise including air runs about $95 total. We've had to cancel two cruises because of an illness that arose, and we would have been out about $6,000.00 That $95 was money well spent.
So Peter, which credit card covers if you have to cancel your cruise? None of mine seem to.