Does anybody know if the car rental agency will "hold" an amount over and above my rental fee on my credit card, in case of damage, etc? It has been years since we rented a car, but I remember having to have $500. or so available to be held. I have about $1600. available credit, but I wanted to keep it available in case of an emergency. We are renting through Dollar, do they hold a set amount and if so, how much?