That's not how it ends up working, though. People just share screenshots or tell friends of the broken website and people stop using the website not uBO.

And there are sites that will throw up a banner that says 'Adblockers might break this, if you have problems disable your Adblocker and try again' which is pretty effective. Funny enough, in my experience, sites with that banner tend to work with uBO enabled (probably because they're testing it).