The message
from Adam Funk contains these words:

James Thurber's story "The Car We Had to Push" mentions an aunt (I
think) who worried about electricity leaking out of fixtures and
sockets that didn't have lamps or plugs in them. It includes a funny
cartoon of her looking at a light fitting for leaks.

My grandma used to put Sellotape over the holes in unused sockets.

--
Skipweasel
Pay no attention to that man behind the curtain.