@GossiTheDog I think I was mistaken anyway; 2.2 Level AA doesn't forbid CAPTCHA altogether, but is stricter on their "type":
"Level AA allows the use of CAPTCHAs, but with specific conditions. CAPTCHAs should use common objects rather than relying on complex cognitive tests. This means that CAPTCHAs should involve tasks like identifying objects in images rather than solving puzzles."