I guess he at least had the excuse of having three 3-ways in each box, but I can tell of somebody who managed to mix up a simple 3-way switch with only 3-conductors (plus ground) in the box. And he started out with them all in the right place!
It was a neighbor's house that was being completely stripped and refurbished. As the living room has three doorways, I wired the light with two 3-ways plus a 4-way.
Well, his friend came over to help him with the door hanging and trims, and for some reason had to remove a small section of drywall which was already up. It included one of my 3-ways. I wasn't around that day, so this friend removed the switch himself and replaced it afterward, despite my neighbor's reluctance to let him touch the wiring.
Then my neighbor found he could only turn on the light from the other doorways if this switch was in one position. Obviously his friend had swapped over the common and one of the travelers, but apparently he then insisted that this was correct, and that it was impossible to have the light controlled from three doorways in such a way that any switch could turn it on whatever the position of the other two, even though my neighbor told him that that was precisely how it had
You'd think that as he started out with all three conductors on the right terminals that he could have managed to replace them properly.
When I returned home, my neighbor caught me, explained what had happened, and asked me to have a quick look. Imagine the surprise on his friend's face when I just swapped two wires over and it worked as before!
[This message has been edited by pauluk (edited 11-28-2004).]