Here is the problem with these detectors and why they should never be used, period. They make the very stupid assumption that all ad blockers are browser blockers and can easily be disabled by the user/visitor. This is a crappy assumption, pi-hole, and pfblockerng, are dns and router firewall level blocking devices respectively. These will block ads on an entire network, not everyone on the network may have the ability to change these ad blocking settings even if they wanted to.
Thanks for pointing this out. I did think about the pi-hole scenario, which is why I provided links to the article's Markdown file in GitHub. I also just realized that my adblock detection doesn't work with uBlock Origin. I'll need to do some extra work on this one.
So many sites, so little time! If a site wants me to jump through hoops because of blocking ads, well, there's always lots more sites, more than I'll ever have time to read.