The TDMRep protocol [1] is supposed to tell scrappers used for text and data mining whether a ressource can be mined or not. Naively, I would say that a website which explicitly express not wanting to be included in training data would also be considered not wanting to be pulled by agents. I know it's not the same thing, but it still itches me a bit.

[1] https://www.w3.org/community/reports/tdmrep/CG-FINAL-tdmrep-...