Vehicles can be driven with or without seat belts it really depends on what the law was at time of manufacture - you only have to look at older classic cars or what year rear seat belts became compulsory for manafacturers to fit - biggest problem would be the carrying of children or minors due to them having to be strapped in.
Passenger safety is the worrying part not having or using one and being involved in accident but motorhome rear seats certainly aren't as secure as rear car seats
Passenger safety is the worrying part not having or using one and being involved in accident but motorhome rear seats certainly aren't as secure as rear car seats