I thought most modern cars had a sensor that detected if someone was sitting in the seat, and only fired the airbag if there was actually a person there. I k

I thought most modern cars had a sensor that detected if someone was sitting in the seat, and only fired the airbag if there was actually a person there. I know my last rental car (I drive an ancient jalopy) had a little 'passenger airbag disabled' icon that went away when a passenger sat in the passenger seat.