If I let someone borrow my car does my auto insurance cover this?
Yes, if you give the person permission then your car insurance will cover them on a primary basis. So even if the person borrowing the car has their own car insurance your auto insurance is still the first to respond. Obviously you want to be careful with who you let use your car.
If your car is stolen then you are not liable for the damages or injuries that occur to others. However you may still have a comprehensive auto insurance claim for your stolen or damaged vehicle.
If the car is in the “care, custody or control” of a professional (mechanic or valet) then they are responsible for your car on a primary basis and your coverage is secondary. Hopefully you will avoid any valet’s like the one in the You Tube link below from the classic movie Ferris Bueller’s Day Off, minutes 4:30 to 8:30 are the best!