If your friend crashes your car or gets hit by someone else, WHILE driving your car, your insurance pays. The insurance follows the vehicle, not the driver.
If your friend gets a ticket in your car, it will not affect your insurance, not unless they mistake him for you. The officer asks for insurance to make sure the vehicle is insured. However, any ticket/license point deduction will affect the driver's license, so his insurance will take the hit.
Confusing, but that's the way it works..
GS