Good point. If the wizard did this you also would never know that such a song existed. Hence your “worst song in the world” spot would be filled with a different song the instant the spell hits.
It shows how such categories as “the worst” and “the best” are only constructions of our mind.
It’s such a shame. Children have so much curiosity for the world.
Adults should realy nourish that, not kill it.
I’ve worked with children in that age range (6 and older) and it’s realy crazy what they come up if you give them a bit of room to experiment with their ideas.