Not exactly. The tensioner is suppose to take the slack out of the seatbelt to help hold you in place. Sleeping in the bunk with it on the floor is not gonna do you any good. If your sleeping in the bunk and your co-driver is driving and has a wreck bad enough to deploy the bags by the time you get to where the passangers side air bag was it will have already deflated and your eating dashboard. I don't suggest sleeping in a bunk with out belts of it's own while the truck is in motion.
Plus... If you have a co-driver in a cargo van. You'd probably still have the passangers seat in place anyways
Plus... If you have a co-driver in a cargo van. You'd probably still have the passangers seat in place anyways