Yes, which is itself a complicated issue that I haven't sorted out for myself. Some states require that liability insurance be included in the price of every rental regardless of whether or not you have your own insurance (although if you ask, the rental company may still try to sell you additional liability coverage over the minimum mandated by law), some states pin the liability on the rental company (and so they always include liability insurance in the price of the rental), some states require the rental company to check that you have liability coverage before renting you the car (but a customer without liability coverage might be such a rare occurance that they fail to do so); You may be insured for liability by renter's insurance, homeowner's insurance, accident insurance (from your CC company), or uninsured/underinsured insurance held by the rental company. You may be insured for liability by one of these insurances, but it still may be illegal for you to drive, in which case your primary concern is not being insured in the case of an accident, but getting in trouble with the police. I'm not sure how police check for proper insurance on a rental, but it probably varies by state.

Has anyone figured this part out? Most credit card companies don't offer liability insurance for rental cars at all, not even secondary.