I've learned from a friend's past experience to
never count on this. He had rented a car and didn't take the rental insurance. Unfortunately, he also didn't have the type of credit card to give him extra insurance through the credit card company. He had parked the car in a lot, thinking it would be quite safe there. Unfortunately, a person in the spot in front of his car didn't see his car and accidentally backed up into his car's bumper and then drove off.
When he dropped off the car at the rental agency, of course they noticed the minor dents & scratches. That's is what they DO when you don't take their insurance. They NOTICE EVERYTHING. If the car was his own and he brought it into any repair shop, it probably would have been $200-$500 to fix. Since he
hadn't bought their insurance for the mere $15 a day, where he could have walked away free & clear, the rental company charged him
$2000. And YES, he did have to pay the whole thing. They chased him for months as he didn't have the full amount. $15 a day was peanuts in comparison to the $2000. The rental company probably didn't even fix the bumper as it really was very minor and didn't hinder driving. It was cosmetic damage.
When DH and I went to rent a car of our own several months later, and they asked us if we wanted the Collision Damage / Loss of Use Waiver for the extra dollars per day. I looked at DH and he said, "Remember what happened to Jeff?" I paid for the rental's insurance.
I don't know what the credit card companies actually pay out or how much or when. I wouldn't want to be stuck with the balance for something that wasn't clearly explained & covered in the fine print. I also don't want to get stuck in a maze of red tape and paperwork as I try to get my credit card company to pay out, but for some reason they are dragging their heels, saying they lost our file, need more proof, etc., no matter what their fine print promises. Meanwhile the rental company is coming after US. When we're done with vacation, I want us done with vacation. Not on some new "journey" we hadn't counted on.