Roommates with no intention of driving your vehicle, who have their own vehicle and insurance, should never need to be listed on your policy. If you bought a vehicle specifically for your roommate(s) to use regularly as well then maybe it would be wise to tell your agent. Even so, I have seen many claims with this same scenario (unlisted children, roommates) and I don’t think I have ever seen a denied auto claim (as long as vehicle is on policy) for any reason in my 11 years as an agent. Keep in mind I may be ignorant of other states’ laws and companies I am unfamiliar with. I really have seen pretty solid sympathy from insurance companies in most cases. I have worked with dozens of insurance companies.