Yeah, I used to do that. I'd put bad actors into a randomly generated never ending link farm. I'd put a special link in my robots.txt and any bot that visited it, I would assume was a bad actor. This link was not accessible from any other location.

The results were striking, how many bots just stupidly tumbled down the random link rabbit hole. I'm not sure what they were searching for, but all they got from me was gobbledygook text and more links.