This doesn’t work.

As soon as the spoon gets wet enough from the boiling over liquid the surface tension of the liquid is unaffected by the spoon and it will boil right over. Might give you a few seconds extra to catch it, but that’s about it.

Source: me. Tried this silly trick and ended up with a wet stovetop. Right up there with the other useless kitchen hacks like the hole in the pot being meant as a stir spoon holder. No, it’s not. It’s just a hole that some “life hacker” stuck a spoon in and told everyone that this is what it was for to get clicks.