I pull DD’s quite often And in ten years i twice had a fault with the suspension and it had raised to max height on the journey back (both times trailer was empty) only way it would reset was to lower it totally then let the air build up. Pressing the reset button in the back of the trailer failed to work. Both times i knew i had a problem was a booming sound when you go under a motorway bridge. So the driver may not be a moron he may just got a fault with the trailer.