So what exactly is the tradition of the "zap?" Is it a pretty universal thing that all naval aviators would know, or is it a small privileged group?
I may be wrong, but I'd say it is rather universal.
I'm not exactly sure of the tradition of the zap. I seem to recall that it came about in the early days of the carrier Navy. When multiple carriers were working together, it wasn't unheard of for a pilot to land on the wrong ship. His plane got zapped while he was waiting to be launched to get to the correct boat. Sort of a memento, if you will.
I first learned about it when the Italian H-1's came to our squadron. I was doing my time out in the line shack when we were notified that we would have to recover H-1's and move 'em to our hangar. After the brief, the LPO asks if anyone has any squadron or Kaman stickers. I had a few Kaman stickers so I raised my hand. He then took me aside and explained the intended use of the sticker and we planned our strike.
Later, when I was on deployment, we would zap aircraft that landed on our small boy with a stencil and spray paint (white for dark aircraft (CH-46) and red for white and low-vis (H-3 & H60). One of the det personnel would go out with the chock and chain boys and zap 'em just before they'd take off. We hit the CH-46 from the oiler twice before word came back that if we hit them again, they'd stop bringing us our mail.