That's a very good question, one my wife and I would like a firm answer to.
Our motor home was built in 1995. The only seats that have seat belts are the two captains chairs. I guess people in 1995 were a lot harder to kill than people today.
So, what's the deal? Do our other seats need seat belts or don't they? And, where do we find these seat belts? And what's the standard for seat belt installation?
Our captain's chairs are simply bolted to the plywood floor, and the seat belts are bolted to the captain's chairs.

Doesn't sound very invincible to me. Is it OK for other seat belts to simply be bolted to the plywood floor?
Inquiring minds would like to know.
Jim