I've been having the same issue with mine. I posted an explanation with solutions on the above mentioned thread. By the way, what did the Apple rep tell you?
I may be misinterpretting, but if its just a little shock, its been an issue since the early powerbooks.
The trick to get rid of it is to use the long power lead, which has a ground plug (at least in Australia, unsure about the states), rather than the very short plug. Its a pain carrying around the extra length of cable, but no zappy is a lot better.
I'm having that sock too...![]()