Maybe more of a legal than ethical consideration but web browsing AI makes scraping trivial. You could use that for surveillance, profiling (get a full picture of a user's whole online life before they even hit Sign Up), cutting egress cost in certain cases. Right now CAPTCHA is actually holding up pretty well against web browsing AI for sites that really want to protect their IP but it will be interesting to see if that devolves into yet another instance of an AI vs AI "arms race".