據說好處是：

If your student doesn't take a car to school, we recommend that you keep him listed on the policy for a number of reasons:

• He’ll be fully protected if he returns home for a weekend visit and wants to drive.
• He will have insurance protection when he’s driving a friend’s car while away, and that vehicle isn’t adequately insured.
• Even if he doesn’t take a car to school, he’ll be fully protected if he’s hit by a car while walking or bicycling, or while being a passenger in somebody else’s car.
• Keeping him on your auto policy maintains continuous insurance coverage, which may be beneficial when he gets his own auto insurance policy.

http://www.autohomeboat.com/research-center/real-life-situations/teen-is-going-to-college