Wear Your Seat Belt, The Odds Are With Them
Even though you "imagine" that seat belts wouldn't help there are instances where they would. Accidents happen when you least expect them.
One example might be, entering unexpected heavy fog on the highway, and you slow down a lot as you panic and disappear into the fog. The truck following you, still going full speed, rear ends you and with the belt you don't go out of the window.
State Laws for seat belts
FWIW, This link has some old data about seatbelt requirements in every state. The newest info I could find is 2006. This is 2005 but is fairly comprehensive.
FYI, our CC has the same seat belts installed as some of the others that own this brand and the same as Peter's Marathon; Drivers and passenger plus belts on the couch. Feds say that being belted in side facing seats (couches) is unsafe.