Some people have absolutely no clue. I work at a big box and I can tell you stuff like this happens nearly every day; although not quite to this extreme.
I've overloaded every kind of vehicle there is with the exception of some medium duty trucks. (2 ton + payload cap.)
The clueless usually ask me if their vehicle will haul the load, and when I don't think so, I get disregarded. I obviously don't know what I'm talking about; I only do this for a living. /forums/images/graemlins/tongue.gif