I can most definitely tell you stories of non seatbelt use. Heres a quick one.
4am, guy returning home from work falls asleep and drifts across the center line doing 55-60 mph. Clips a truck coming the other way, and rolls his Ford Explorer. Hes ejected, and is found (eventually) roughly 75 yards from his SUV in the ditch. His ear falls off in my hand while I'm holding c-spine. He never made it out of the hospital. He would be alive if he was wearing a belt. Even though he rolled it, there wasnt any major intrusion into the passenger cabin. And all airbags diployed. They just didnt do him any good, because he wasnt in the car.