Can a junior operator lose their license in mass for failure to use seat belt?

It can save you from horrific brain injuries, and may even save your life by restraining your body if you are in a collision.

they keep the space your body can move around in restricted.

Yes, it is advisable, for two reasons: 1). In most states, it is the law. 2). In a data base of many thousands of car crashes, it became obvious that drivers and passengers who wore seat belts died...

yes

Yes, it is the law.