I know there are lots of devices around to discourage or prevent rug-rats from poking found- objects into power sockets.
The devices all cost cash you don't have, or you just never get around to fitting them.
So ... since having had a big scare once, and stuck with minding a great-grand rug-rats
again in an unsafe house, here's what I did.
I cut pieces out of plain white [hence unattractive] shelf-plastic and pressed them over the offending sockets when the kids couldn't see me. No rug-rat even looked at them.
Here's the halfbaked bit.
Electricity suppliers, in need of a good-guys image could/should give away attractive cards of [plain] SocketStickers with the usual self-praise all over the card. No matter, if just one sticker saves just one child from harm.