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?
According to this page, you could attempt to argue “lack of causation” if there was no connection between you not wearing a seat belt and your passenger getting killed.
But, the person who died is buckled in. That’s how I read it.