As someone who frequently drives with my arm out the window, that would certainly be concerning. I can see some considerable safety benefits to containing unrestrained people in the vehicle (rollovers tend to result in ejections, which have a high mortality rate), but at least from a management perspective, I'd much rather let a negligent person be ejected 50 times than keep 49 of them in the vehicle and have 1 sue us because we cut their arm off.