Wirelessly posted (BlackBerry: BlackBerry8530/5.0.0.1030 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/417)

"typically state laws require an owner of a vehicle to be financially responsible, either by carrying liability insurance or being self-insured, so if an accident is caused by a renter, there will be a source of funds to go after other than the renter's funds."

While that's true in most states, we don't know in which state the OP will be renting. And state minimums are typically paltry. In some states, the rental car company can still go after the renter for damages paid out to third parties. So it's a very tricky field.