Note the 800 lb. ballast box shown in that photo. That little 2-ton wagon will never develop the lifting force on that drawbar required to lift that ballast box, given the angles and weights involved.
A trailer with a rigid drawbar is a different story, as any weight placed aft of the rear axles can add to this lifting force. But in this case of a drawbar hinged at both ends, the only lifting force would be the forward force of the wagon (max 2 tons times sine of downhill inclination angle) times the sine of the drawbar angle between wagon and trailer. That's going to be a very, very small fraction of the ballast box weight, so never able to lift.
But even without the ballast box involved, it'd take someone lifting their 3-point pretty high on a downhill stop, to provide enough angle to develop sufficient force to lift the 50+ lb. weight of the 3-piont + drawbar with a wagon that small. Not recommended, obviously, but probably still not a likely scenario.