The brother-in-law trumps the doctor:
“My brother-in-law says that you’re safer without a seat belt.”
Oh, crud. I just hated that answer, because it left me nowhere to go. Even if the brother-in-law was an unemployed high school dropout whose knuckles dragged the ground when he walked, he was known in the family as the world’s leading authority on seat belts. All arguments failed in the face of such expertise. I would make a feeble try, such as, “National statistics show a much greater chance of survival with seat belts,” the patient would again cite the brother-in-law, we would call it a draw and go on to another subject.