Wait a second...I weigh more than 160 lb. Does that mean that if I stepped on the hitch of one while trying to get up into the bed it might break?

Based on the evidence, it should take more than just stepping on it - it seems to break under a big dynamic load. The cast aluminum appears to be more brittle than a steel frame.

But who knows, really. I'd say "not Tesla", but they did add that warning to the owner's manual...