I had a jeep that I sold my younger brother back in the 70's, he was still in high school and did stupid stuff. The back seat was just sitting in there not bolted down. He took it up a mountain road with 2 of his friends and on the way down ran off the road and rolled. The 2 in front stayed belted in but the guy in back got thrown out, the seat landed on top of him and the jeep rolled over it. He came out from under the seat with just minor scratches and bruises.
