We're really at the mercy of these companies and often don't find out til a mishap if you are covered or screwed. I actually was GLAD that I bought additional insurance on a car rental from Enterprise a few years ago, for a trip I took down south. I had minimal coverage on my old car(which I didn't want to chance taking over the steep mountain road) but I doubt it would have covered having the rear end of the Nissan I rented crumpled, which I discovered when I returned to the parking lot after sightseeing. Insurance covered it totally and it was a relief. Replacing those bumpers can be more than the cost of a small used car.