Given his comment about sliding off the couch and building a charge, I would guess the pin has a ground...otherwise it would not have arched. Grounding the pin keeps IT from shocking you if there is a short (takes the path of least resistance), however there is no way to protect yourself from building up a charge outside of maybe metal spikes in your shoes. Now the bigger question is why the electrostatic charge affected the machine. It obviously grounded through the wire harness, which is possible, depending on what was touched first.

I didn't say the ground was proper....I just said there was a ground somewhere in order to get the arc. Absolutely agree with what you said....that is what I meant when I said the ground had to have gone through the harness in order to affect the machine. I think we are in the same ballpark...you just said it better than me. lol