Heh, I've always called this the map makers trick (found an article about it here: https://theweek.com/article/index/241967/trap-streets-the-cr...) although I guess that is specific to putting a small amount of fake data in your dataset to prove someone else used it. The hellbanning metaphor does fit for return large amounts of poison results.

It could be like spiking trees I guess, but that depends on the potential for harm. I just looked it up and was surprised to find that only one injury has ever been reported due to tree spiking. I guess it's a better talking point than actual tactic.

And like lukejduncan said, this is definitely done in practice.