My understanding is that AI scrapers rotate IPs to bypass rate-limiting. Anubis requires clients to solve a proof-of-work challenge upon their first visit to the site to obtain a token that is tied to their IP and is valid for some number of requests -- thus forcing impolite scrapers to solve a new PoW challenge each time they rotate IPs, while being unobtrusive for regular users and scrapers that don't try to bypass rate limits.

It's like a secondary rate-limit on the ability of scrapers to rotate IPs, thus allowing your primary IP-based rate-limiting to remain effective.

Criminal convictions in the US require a standard of proof that is "beyond a reasonable doubt" and I suspect cases like this would not pass the required mens rea test, as, in their minds at least (and probably a judge's), there was no ill intent to cause a denial of service... and trying to argue otherwise based on any technical reasoning (e.g. "most servers cannot handle this load and they somehow knew it") is IMO unlikely to sway the court... especially considering web scraping has already been ruled legal, and that a ToS clause against that cannot be legally enforced.

Many are using botnets, so it's not practical to find out who they are.