So, this might sound like an odd question, but at a very simple ethical level there is a clear problem with using an adblocker. There is, after all, a very clear understanding that ad providers are paying them for your access to the content or put differently: You pay for the content by watching those ads (of which selling your privacy is often (though not always) a part). Unethical however hardly means directly unlawful/illegal, so I have often wondered about the legal mirror of those ethical rules.
Our hypothetical case
So, some ToS's explicitedly have statements like
You agree not to alter or modify any part of the Service.
taken from the YouTube ToS. So let's assume our theoretical service has those as well possibly even explicitly addressing adblockers. Note clearly that I am not saying that the quoted statement is the best legal way of putting this, it's purely an example.
Now, lets say that a user uses this service for a year whilst an adblocker is running. Lets also say that the user has signed up for the service and explicitly consented the Terms of Service. Is there any way that the service could lawfully get this user to pay up for his usage of the service (the loss of income)? Or if not, is there any form of 'punishment' the user could face? (Beyond being blocked from the service, but he could also be blocked from the service even if he didn't use an adblocker if the service answer would feel like it) And if yes, does it require such an explicit segment in the ToS or is this already a natural given?
PS. I have selected the united-states as the main focus of the question, simply because it's most likely to get a quality answer, however if you also know how the same would work out in a western european country I would love it if an answer could include a very short rundown of that as well.