I can’t get a good answer for this as Google is thinking I’m talking just solely on the driver. I’m including passengers who don’t. I’ve seen PSAs that tell you the dangers you pose for others as well when you don’t wear a seatbelt. So if you don’t wear a seatbelt and that results in someone being killed could you not wearing a seatbelt mean you get a manslaughter charge?
I’m having a hard time imagining an accident caused by not wearing a seatbelt… I guess maybe being thrown from the vehicle and hitting a passenger in another car who was wearing a seatbelt?
Caution CW: contains simulated road accident resulting in death - was considered safe for TV in the UK
I think OP was picturing a situation like this.