Lots of dealers push the '1/2 ton towable' idea based on the 5'ers dry weight. My 5'er is 'dry weight stickered' at 7185lbs, with a pin of 1385lbs. After we loaded 90% of our normal camping gear on our 1st outing, we went across the scales at 6500lbs on the 5'ers axles and my trucks rear was at 4700lbs. Empty trucks rear weight is around 2750-2800lbs. So in a nut shell that '1/2 ton towable' had a pin around 19-2000lbs and weighed in at 8500lbs or so. Not a lot of 1/2 tons are going to be happy with 8500lbs and near 2000lbs on the pin. Now throw in a 54 gals of water and your near 9000lbs.
Problem is people just look at the max tow rating and think they can do it.