Sorry if my comment came off as a little blunt, as I intended no rudeness, but I'm tired of knee-jerk comments regarding Russia. In your linked study they measure number of buckled drivers as slightly more than 50%. That's somewhat different to jamming seat buckle altogether with a key holder, don't you think?
Rear seat passengers do not wear seat belts indeed, but that's another story: lots of cars simply don't have them and it's not enforced by law.