They're not; they risk harming other people in the vehicle and there is extra effort to recover the injured body of someone from an RTA if that person wasn't wearing a seatbelt which puts emergency services at increased risk of harm.
Re:John Nash Has Died
by learnstats2 on Sunday May 24, 2015 @12:20PM
(#9596662)
I'll repeat my point in your terms: By forcing people to wear the seatbelt, other risk-taking behaviour is increased, which appears to result in more RTAs.
The evidence on either side is not enough to justify bankrupting fines.
If someone makes such a deliberate and conscious decision not to wear a seatbelt, maybe you could assume they have their own reason for that.
It's not even clear that forcing people to wear a seatbelt saves lives. It may increase the risk to other people, if people are seeking out a level of risk that they're comfortable with: https://en.wikipedia.org/wiki/Seat_belt#Risk_compensation