It's actually not easy to detect adblock use. Popular ad blockers actively try to evade detection. If the intent is to let publishers decide whether to allow adblock users or not, it should send an easily detectable flag.
For that matter, wrap your primary content in a div with a class of "ad" ... then users won't even see the content, and you can replace it with a notice to disable adblock and refresh the page.
Much harder to get right than you'd think and if you're a big site it's worse: the block lists will be updated to "whitelist" your test ad.
It's difficult for publishers to even accurately measure what impact ad blocking is having on their business.
I use AB Edge. I've visited Reddit, they posted a "we notice you use an ad blocker, if you like us, please think about whitelisting us." They could have just refused to serve the content. Either way would have been acceptable; it's my browser and I control what I see, it's their content and they control where it goes.
In that case I whitelisted Reddit. Nothing on Reddit remote-controlled my machine, it just initiated a brief "conversation."