Are our Slants "Unsafe"?
If someone doesn't want to wear or have one it will not kill you
But it very well might. Y'see, belted drivers tend to remain conscious and in position to control the vehicle after the first impact (which may be relatively minor), so they have a chance to control where the car's going to prevent or at least mitigate the second, third, and subsequent impacts. Unbelted drivers tend to get knocked out of control position and/or unconscious so they
can't control the car after the first impact, which means a much higher likelihood of their car causing additional injury, death, and/or property damage. Even the driver who is not knocked out of position and/or unconscious is much less able to control the car if he's not belted in, because he's putting most of his effort into clutching the steering wheel fighting to stay in position.
You may not like it because it spoils your "My choice not to wear a seatbelt doesn't affect anyone but me!" argument, but it is how things work in the real world.