Additional driver fees on CA car rentals?
 

I have an upcoming trip to SFO and was wondering if you California experts could clear up some conflicting information for me. In digging through the archives on some other travel sites, I have found some vague information suggesting that rental car companies are not permitted to charge additional driver fees in California. However I cannot find any recent information to confirm this, nor can I find any such language in the T&C's on any of the rental car companies' web sites (except for Fox which seems to exclude California from the list of states they charge additional fees in).

I've never had to pay additional driver fees in CA in the past, but the additional driver has always been a family member. In this case, there will be three non-related persons driving the car.

Anyone have some insight on this?

Just 1 data point, but my BF and I just picked up a car at SFO yesterday from Enterprise. He added me as a second driver and I thought there would have been some extra fees since I'm not a coworker of his and we're not married and have different last names. We asked the lady if there was an extra fee and she said no since I'm over 25. Only drivers under 25 would incur fees and those would be under 25 fees, not additional driver fees.

I thought it was because he was on a corporate rate since my corporate rate allows coworkers without a fee.

I know enterprise offers this service for free. I'm not sure if its different at airport locations.