But do kids ever sit up straight in the car? Mine do the same thing, lean on the arm rest, usually toward the center so that they can bug each other as much as possible.
When I was a teenager - back before any seat belts were required by law - my dad was (justifiably) concerned about me and the '62 Studebaker convertible (with the police pursuit engine with Holley 4bbl). So he installed a roll bar and hooked up two aerobatic harnesses to the roll bar and the floor frame (he was a pilot from age 13 until he hung up his helmet and goggles at age 79 - now 82).
I thought it looked rather cool than otherwise (I had just soloed at 16) and was able to carry it off despite some incredulity on the part of my friends. The fact that I could lay 20 feet of rubber in all three gears helped . . .
Good point.
The NAZIs should be making us buy STRAITJACKETS and put them in iron seats with roller-coaster bars at their chests and hips so they CANNOT move.