So, I asked my hubby about that, and he ran off and grabbed his multimeter... and lo and behold, it is NOT CONDUCTIVE.
My hubby, btw, has an open offer on the table to take any E-Nano that anyone wants to toss due to this fear.
You know what... GFCI outlets are great. If you use a blender, a toaster, a food processor, a curling iron, or a hair dryer, be sure that they are all plugged into a GFCI outlet. My E-Nano just happens to be plugged into one, as it is in the kitchen, and EVERY SINGLE outlet I have in there is GFCI, and has been, since we did our remodel on the house. I have taken it to the livingroom, and plugged it into a standard outlet, and have no worries.
A spark at an outlet when plugging in can indicate a short anywhere at all in the cord (never pull on a cord to unplug, always use the handle part of the plug), a fault in the cord, something might have gotten wet, OR it could also be a fault in the outlet. Based on the feel of the cord, my hubby considers that the weak spot... it may have been a defective cord, with a really weak spot in it. He said he hopes that Andy got that unit back, so finding out what happened can happen. He's kinda betting on the cord.
Maybe the first few times you use a Nano, plug it into a GFCI (try your bathroom outlet) and verify that there is no defective cord issues, then go use it where you like.