Yes, on the pressure washer story you can say that had it been the black wire shorting to the frame then reversed polarity would have saved the unfortunate victim. It's the missing ground connection that was, to my mind, the primary reason.
I write for a monthly "Motorcaravan" journal (RVs to you) here, and the reverse-polarity question is one which seems to cause a lot of queries, especially among people visiting the Continent due to the reversible plugs etc. mentioned above.
As the 240V systems of all recent RVs here have a GFCI on the hook-up, swapped H & N really isn't such a problem as many of the readers have been led to believe.
