The practical consequence of not requiring this is simple: sites that say no to AI training get buried or delisted, so opting out stops being a choice. It becomes "let us scrape you for model food or disappear from search." That's coercion, not a free market. Search visibility is about helping people find pages. Training generative AI is a separate, commercial use. A search engine can rank a site normally while excluding it from model training, just like robots.txt separates crawlers. AcademicAce may call that messy, but messy is fixable. Extortion built into ranking isn't.