A while back I had a few sites warn me about ad-block, but I haven't seen it in a while.
Unfortunately, LastPass started acting up in FireFox a few weeks ago and I decided to give in to Chrome, again, so I've happily returned to uBO.
I go back and forth on which to install for people that routinely come to me for help (I'm a developer, not a helpdesk, dammit!). I'm not sure if it's still the case, but months ago I actually did receive a call from my father when he attempted to install an open-source PDF creation tool that he uses at work on his home PC. It was hosted by SourceForge which uBlock had large swaths of in its blacklist. The installer did contain a bull$#*+ toolbar (several, actually), but he's familiar with avoiding crapware directly placed within installers (and to avoid "Express Installations").
Doesn't mean it's not happening. Maybe people assume the specific page is just broken.
I'll get a phone call every time when a piece of crapware causes videos to play on Google's normally spartan search page, or ransomware is asking for "... something called a 'Bitcoin'? I don't remember installing a 'Bitcoin'."
They don't bother calling when one of the thirty places they get news from stops working.
Despite all of the talk about "blocking the ad blockers", I've yet to receive a phone call from anyone saying this or another web site didn't work, "Can you fix it?" I'm guessing their usage is limited enough that they don't encounter it (my dad does visit Forbes, but I haven't heard complaints).
There's no way I'd surf the internet these days without ad blocking enabled and I rarely white-list sites out of concern for my data. It's becoming as important as personal firewalls / antivirus once were.
[1] There was a brief period during the time that they received the malware that MSN had been hit by malvertizing and they had that as their homepage, but it could have come from elsewhere. The bottom line was that there were no sites in the riskier categories that were in their browsing history and my parent's proficiency does not include a good understanding of "incognito browsing".