As now countlessly proven by all the lawsuits or potential lawsuits abound, it's still pretty easy to show what ai models were trained on. It's the entire reason a company is paying reddit for the data instead of scraping it in various ways (ways that were easier before reddit closed off their api). Maybe in a few years time they'll have it worked out to where there's no way to pick up on where an ai scraped it's data from, but they aren't there yet.