As you said, they won't let you drive the car out

if you don't buy the liability. As know, most rental car has basic liability withlow limit 15k/30k(you can ask them if they have it, if they say no, you can ask, oh, I think it's illigal, since it's required", then they will tell you the truth), if you buy additional, limit increase to 1Million, so you are not necessarily have to buy it, but if you credit company don't cover the damage waiver(for the rental car only), yo/d better to buy the damage waiver. If you have a good credit, you don't have to buy anything. Am I right? Thanks.