A saying that comes around often whenever epeeists
are preparing to do some fencing.
It comes from the fact that the director of the bout in epee, unlike foil or saber does not really need to know that much about directing. When girlie men or unthinking brutes fence, there is a rule known as right of way which, to be brief, states the circumstances under which you are allowed to hit me (which, in a move which makes no sense to the sensible fencers, is not whenever you want). The right of way node has a far better discussion of this, so I will not go into depth.
Suffice to say, in foil and saber, the director must watch the bladework to see whether hits count. In epee, whenever the tip hits someone, it counts. And with modern electrical scoring systems, whenever a hit is scored, a light goes on. So an epee director has a really, really easy job--whenever a light goes on, give that guy a point.
Thus the saying--a trained monkey could easily remember whose light went on...
This is not necessarily true in extremely high level epee. They move fast, and often attacks occur near the edge of the strip, so among other things, directors must determine whether the attack occured before or after the fencer went out of bounds.
Lastly, you might not want to use this around one specific fencer from my club. Not that you are likely to meet him, but, well... He once made this remark when someone shouted out, "Can someone direct our epee bout?" In response, somebody directed the bout--as a monkey--complete with walk, hooting, grunts, and gestures. Now, that fencer gets annoyed whenever anyone mentions it.