Something seems fishy to me.

I would try to find out preciesly what the "expert" really said. He may have said that current code requires the outlet in question to be a GFCI outlet (assuming it's for a kitchen counter and not for the freezer) and may have said that the nail transmitted the heat from the box to the wood, which could be true. Someone else could than have transformed his statements to blaim the builder/electrician. Then again, the "expert" could just be full of sh*t.