Fairly early in my pinball "career" I was introduced to the inside of the door of a North Star. It hurt. It wasn't funny!
I believe in shrink wrap. Very good for those hard wire type switch arms that manage to always ground you.
Or you could go with the extra grounding. Either way, own a older Gottlieb? Do this or prepare for the best shock you have ever received since high school when you grabbed the plug wire on your buddies chevy!