This is very true. As someone with quite the experience with materials published under Penguin, Scholastic, etc. you effectively have a "dictionary attack" on the matter, rather than true "brute force," but that still leaves quite a list to compile to send to each and is easier for larger titles than smaller ones. I wonder how that leads to a bias in what materials get used for training. You are not getting many local self-published books this way.

It is almost like we need a "for use for training" agreement across the board. This would not fix the current issues (at least without substantial work), but going forward would allow for creators (or publishers/rights holders) such as this to designate a work as crawl-able for AI. A robots.txt just for Claude.