When I first went otr we hauled 2 secret service vehicles from Davis Monthan AFB, Tucson, to FBI facility in Quantico, VA. The boys who loaded in Tucson chocked the wheels, nailed to the bed but didn't set the brake or put it in park after maneuvering the suburbans into place. All was fine until VA where I came around a tight corner and the trucks were lined up for the scale. I slowed abruptly and heard a crunch come from the trailer. When I got out to inspect, the trailer nose was pushed out and the vehicles were piled up in the nose. Fortunately for me the suburbans were surrounded by a tubing cage welded to the frame. When I dropped them in Qauntico they didn't say boo.
I learned about double checking my load.