My Thai sister-in-law gets in the back of the car and buckles her seat belt knowing that I wont move unless she does. My wife (her sister) is already in the front passenger seat buckled up.
Once moving. I watch my SIL in the rear view mirror as she surreptitiously unclips her seat belt thinking I wont notice.
I pull in and park on the shoulder and say to my wife "Seat belt warning" pointing at the dashboard, (usually the parking brake warning light since there is no visual warning for rear seat)....and make a show of checking my wife's seat belt until hearing a 'click' from the rear seat. At which point I release the parking brake and carry on driving. 😏
In retaliation, if my wife is driving and the SIL is in the front passenger seat, she never wears her seat belt although my wife always wears hers.
In contrast, a builder doing a job in our house asked for a lift. Climbed in the back seat, located the seat belt anchor and clipped up. I said (through my wife) "That is the first time ever that a Thai has got in my car and secured their seat belt without being told" He then told us that, a few months previously he had been driving his twin-cab pickup on a good road, with thick trees on both sides. The grade was slightly uphill, road dry with sunshine and approaching a blind sweeping bend to the right. Without warning, an SUV at speed came around the bend sliding into my man's lane and collided head on. He estimated the impact to be around 120 kph. His airbags blew, the windshield shattered he 'came to' pickup hard against the verge metal barrier. His first thought was for his wife but he could not see her as her seat back had folded forward. It transpired that their daughter with infant son on her lap (no seat belt) had been sitting behind her mother and had been thrown forward, by the impact, into the front passenger seat back breaking the locks and folding it flat. She then exited the vehicle through the windshield into the windshield of the SUV killed instantly along with infant.
Lifting the back of his wife's seat he found her, a petite woman, jack-knifed into the footwell, bruised but otherwise uninjured. She had not been wearing her seatbelt.
The driver of the SUV had also been un-belted and had been thrown through his windshield and killed.
My builder said he learned that day that seat-belts can save lives and always wears one when in a vehicle and has taught his family members the value of 'buckling up'