Interesting question. Given the incredible latitude that courts have afforded to the CFAA, if a site put in its TOS that accessing it with an ad blocker enabled is prohibited, would that be actionable? Could ad blocking companies in such a case be held liable for tortious interference and/or conspiracy to violate the CFAA?

I don't know the answer, but I can certainly see a lower court ruling that way before it is decided by the Supreme Court. To be sure, that's where this would be headed if this kind of technology becomes ubiquitous and effective.