That is a valid question but I think if it is equipped with belts you have t wear them. Lots of grey area with this machine. I just try to color in as much as possible and avoid conflicts - unlike my younger days, I am too old to be handcuffed to that steel bar in holding.
I can't speak for the other states, but in Arkansas it is still classified as a motorcycle, and you do need an endorsement. With that being said motorcycles do not have seat belts and i am not going to be that guy to write a seat belt ticket in a SS. I do understand the personal aspect of wearing it for safety reasons though.