I was trouble-shooting a bad 3-way switch. Removing the switch plates from both boxes revealed large holes broken out of the ends of the box where this particular light circuit entered and exited the boxes. Both are 3 gang boxes. This is presumably by the same electrician that didn't tighten the ground wire on the outlets switches. Why would he/she/it do that? All the other wires were done properly (as far as I can tell without cutting into the wall cavity).