Edit: Thanks for your kind comments on disabling contributions. I'm aware of the possibility, this is just a meme.
Contributions in open source projects are great, needed and make the world a better place after all. Therefore they should be declined politely, optionally by giving a reason.
I hereby inform you that I will no longer accept contributions to this post /s.
I do feel like putting an intentional, obvious, but non-issue causing bug in a code base now. Make a contrib guide. Mention needing to read the docs first and check previous issues/discussions first, and make a closed ticket explaining that that bug is nothing but an example bug and that will ban anyone that attempts to fix or report it.
Like a green mnm test for a code base