Rules about advertising could just end up like it did in Portugal. ISPs were advertising unlimited data (on fiber/cable), but the small print stated that there was a limit, which was dependent on congestion/etc.

Essentially, in any given month, you could get throttled/yelled at for going over an arbitrary data cap, which could (and did) vary every month. Given, it was usually above 1 TB, but it was still there.

ISPs got a book thrown at them by the FCC equivalent, saying that if they advertise their product as unlimited, it must be truly unlimited. Literally the next day that decision came out, all ISPs changed their adverts from unlimited to "at will" data caps, which essentially conveys the same marketing message, but isn't a regulated term.

Welcome to the new world, same as the old world, except where we've replaced a word.