I think every jurisdiction has an exception for older vehicles. If a vehicle did not come with them from the factory, which all did by law after a certain date ( late 60's to early 70's) you don't have to retrofit your vehicle and will be legal without them. Common sense ( and lots of statistics) say seat belts save lives. I would NOT drive or ride in any vehicle without at least lap belts, nor would I allow any passenger to ride without being belted up. If only one person in a vehicle is not belted and you are in a collision then that person will be flying around inside the vehicle doing lots of damage to them and others.
