I would observe my princess. See she playing with the switch or poking the hole with things or fingers. Normally i would let her do as she wants, because she would get bored after clicking the on/off switch a few times. Then move to something else. I found that the more u try to prevent them from doing, the more they will play with it. If you are really worried, just switch off the main circuit breaker. (Not recommended because it would give them the impression that all sockets are safe)
Mine likes to go near fan / electric plug too . So dangerous omg . Keep repeating n sound very fiercely to my lo cannot go near or touch it. I will off the switch in the rooms. You can either off switch or buy switch cover case ( but once lo knows how to open ) you may have to use eg cabinet to cover the plug area or hide all the plugs high up