Things They Should Invent: electrical outlet covers that give you a tiny little zap

My Favourite Little Person recently started crawling, which means that, among many many other things, her parents had to put covers in the electrical outlets. Of course, she immediately started showing interest in the outlet covers and trying to pull them out. Her parents told her "No!" and she seems to understand that they don't want her touching them (which completely blows my mind, BTW. I didn't know kids could understand that at such a young age!), but she has no concept of why she's not supposed to touch them. They look benign, they do nothing that's readily apparent, so why are they a "No!"? This is such a mystery that she's tempted to touch them just to figure it out. Her parents have caught her staring at the outlets in curiosity, shaking her head "No" as though trying to convince herself not to touch them because she's not supposed to (which, again, blows my mind! There's already a conscience in that little brain of hers!). They wouldn't be nearly so tempting if she understood why they're a "No!"

Solution: electrical outlet covers that zap you, just the tiniest little bit. It wouldn't be anything harmful, just a very small, carefully measured jolt of static electricity, like you get from shuffling your socks on the carpet on a dry winter day. That way, little fingers will quickly learn why they're not supposed to touch the outlets, and temptation will be eliminated.

Of course, it might be inconvenient to have zappy covers in your outlets at all times. If you frequently have to uncover the outlets to use them, it would be annoying to get zapped every time. If you have household pets that are smaller and stupider than your average baby, they might get hurt. So maybe the zappy covers could come in a set with identical properly-insulated covers. You can put a zappy cover on, let the baby learn their lesson, and then (when they're not looking) replace it with an insulated cover and proceed with life normally.