Originally Posted by mel s
"Stray Voltage", (aka: a "Hot Skin condition"), is often caused by a faulty shore power cord or a faulty electrical adapter and can be deadly.
Yes, it can certainly be serious. Besides the causes you list, it can also be a faulty ground in the power socket, as was the case here.
Originally Posted by garbonz
I use one of these Fluke 1AC-A II EVERY TIME I plug into an unfamiliar source.
What about familiar sources? Do you check it each time you plug in at home?
That's what the OP was doing, it was his connection at home that failed. (It was probably the GFCI that was masking the disconnected ground inside the house, and once it was replaced with a regular outlet the pre-existing fault became evident.)