I personally would check the file before making any claims. I cannot remember the projects, but I have seen a couple ( that clearly didn't stick with me ) that used an agents(dot)md file to basically tell the agents to piss off, in a much more professional way. It's what inspired me to make an agents(dot)md file for my nekoweb pages.

As for it being effective, I imagine it's about as effective as the old robots(dot)txt, but a man can dream.

Edit:

The file is in Chinese, so I cannot say one way or another until I see a rough machine translation.