I think it is a CYA thing but to be safe get one that is RV rated.
I have
This one it fits in my 2 inch receiver and easy to load and I like the way it folds so I can get to the rear door of my large storage area without having to take it off,
As for the bouncing that others have talked about to make it less pronounced You need a good anti rattle device so you don't get so much play in the receiver,thus magnifying the movement and doing more damage to the bike rack.
I have tried almost every Anti Rattle device on the market, most have been no good or so complicated and cumbersome that they are useless. Including the Roadmaster type,totally useless.
Until I found the one at Hitch Rider.
Their
Hitch Vice is the best and easiest one I have come across and it really works.