Though looking at just one list of Nintendo's mass takedown of free fan-games, it seems very likely* it directly resulted in many children being terribly upset (and maybe thinking they'll be sued/jailed)... even if they made their own assets, just because they included a trademarked term in the title/description for something they just wanted to share with their friends. (I'm sure many did use assets, but we are likely talking about decades-old material here)

So it's not that big of a stretch, it's just not guaranteed that we'd hear this much about it.

*= judging by FNAF/sonic crossovers, content/spelling of titles, creepypasta stuff, and likely terrible art if you can still find more than a URL