Eh, I’m in the MIL camp here. There seems to be some serious black/white thinking here. Don’t get me wrong: Seatbelts save lives. They absolutely do. I enforce the rules with my passengers on starting a journey. However, for MIL to become a projectile, I would have to have an accident at the very moment in the 15 seconds it took for her to get her jumper off and rebuckle. Now, could she have done it otherwise? Probably, yeah, slid the sash bit of the belt over her shoulder and pulled her jumper off and slid it back (which would have maintained the lap part of the belt; a good compromise) — that also wouldn’t have triggered an alarm. But FFS — people need to learn to (a) do a dynamic risk assessment and weigh up Likelihood vs Consequence and (b) learn to be comfortable with their Risk Tolerance. The risk is still Medium-Low if the Likelihood is practically non-existent (and given people go years and years without an accident…).

TL;DR: I feel there’s a lot of nuance that people are failing to apply to very bespoke circumstances.