> Hey I wonder if there is some situation where negative SEO would be a good tactic. Generally though I think if you wanted something to stay hidden it just shouldn’t be on a public web server.

At least once upon a time there was a pirate textbook library that used HTTP basic auth with a prompt that made the password really easy to guess. I suppose the main goal was to keep crawlers out even if they don't obey robots.txt, and at the same time be as easy for humans as possible.

Interesting note, thank you.