"What is the danger in this?"
Our first and second travel trailers had aluminum skins. When we lived in town, because of where I had to park the camper(s), I ended up using an orange construction style 100 foot extension cord to plug in the camper to keep the battery charged and for light use inside.
It took a while to figure it out, but sometimes, especially if I were barefoot, I'd touch the door, door handle, or side of the camper and get a tingle shock feeling. Not bad, just enough to let you know ... don't touch this. I didn't think too much of it until one day, one of our kids questioned it happening.
As it turned out, the extension cord I used had the ground plug broken off (on purpose) and I never associated the ground fault with the shocking sensation on the outside of the trailer. When I switched extension cords, it never happened again. Lesson learned.
No, it probably won't hurt anything, as said above, most household small appliances don't have grounded plugs and they work fine. But in an RV that cost thirty thousand dollars, compared to a seven dollar desk lamp? Um ... it's good to have the electricity correct!
