I think it all comes down to the way the factory hitch is mounted to the vehicle. I think a WDH changes the way forces are applied to the hitch in a way that VW engineers did not determine it could safely withstand. They designed and installed a hitch that could support 500# on the tongue and straight pull 5000#. They didn't design for the force that a WDH imposes on the hitch/vehicle. Obviously they could have, but perhaps being a German company that typically operates under european guidelines, it wasn't even considered despite this vehicle being designed and built for the US.