Neither insurance nor the cops would blink an eye. If he uses his bike to facilitate his attack - which he is doing when he blocks my escape route with it - then I have every right to smash his bike and escape from physical assault: "...he is about to attack me with a club...". At that point, most states allow me to use deadly force to protect myself from being clubbed. If I had any doubt about being able to clear an escape route with my car, I could and would use a gun to prevent getting my head caved in. I believe in showing great restraint in using a gun, but I wouldn't carry if I wasn't willing to save my life with one.