I have a 15 month old, if you spend time with them and talk to them like a person you realize that they understand much more than most give them credit for.
We have 'trained' her for a lack of a better word with a couple phrases..."Hot" and "No Touchy"
She fully understands "Hot" means it will hurt her, but it does not always keep her from trying it. "No Touchy" she knows it is something she should stay away from, it also is not 100% and at times she goes to "No Touchy" things in the house simply to get more attention from you as Mom or Dad will now come over and "Play" with her too keep her from damaging it.
Now, with the Reef...she has figured out how to open the cabinet and get to the sump so we keep a chair in front of it to block her access. The chair allows her to get up and see the "Fishies" (She loves to watch them eat) and so far she has not reached up toward the top of the tank. I do plan on getting some form of lock for the stand so the use of the chair is not needed.
And for my own vote, I found the electric fence joke funny as well.