I always thought that an unauthorized driver would not be covered by the insurance provided by either the rental car company or your personal automobile insurance. It sounds like your insurance agent believes differently. I would confirm what the agent advised you, and wouldn't worry too much about the car rental company.

IIRC, some rental car companies make an exception for colleagues traveling together on business, even if the colleague is not specifically listed as an authorized driver. Also, some rental car companies do not charge an extra fee for a spouse, but do require that the spouse be listed as an authorized driver (which requires that the spouse be present with his/her driver's license at the time the car is rented).

[This message has been edited by Blumie (edited Feb 28, 2004).]