> I can definitively say llms.txt is not used by any AI players.

  https://developers.openai.com/llms.txt
  https://docs.anthropic.com/llms.txt
  https://geminicli.com/llms.txt
  https://github.com/llms.txt
  https://docs.aws.amazon.com/llms.txt
  https://openrouter.ai/docs/llms.txt

OP clearly meant that the AI players are not reading and/or honouring llms.txt of other websites when scraping.