The drunk uncle would hook the seatbelt up before getting in so he didn't hear the bell. Said it was safer that way, because he happened to survive a car accident once and claimed wearing a seatbelt would have killed him.
Enforcement was practically non existent and it was generally seen as evidence of government overreach (“who are they that they can tell me what to do?”) instead of good safety practice.
Edit: I looked up a recent study. Apparently 1/3 of drivers in that particular country didn’t wear seat belts in 2021. How they manage to do that with modern cars is a mystery to me.
Click in the belt and sit on it. Or cut off the buckle and click it in place, or order a spare and click that one in if you don't want to damage your seatbelt.
Please don't do these things. If you are in the car, you should have your seatbelt on. Even if you are just sitting in a parking lot.