UPDATE 2 It seems that starting today, uBlock Origin is working to combat this Youtube Block. Mine started working again! Lets all thank the devs of UBO for fighting this fight!
UPDATE So as new info comes out, I'll be posting it here. It seems as if this Rollout Has Several Parts.
Part 1
You get a popup message over top of your video, blocking the screen:
- This is the first sign. If you see this popup AND are logged into a YouTube account, your account has been selected.
- At this stage you can likely close or block these messages with an adblocker.
Part 2
This message will change, indicating that you have 3 remaining videos to watch without ads.
Will insert photo once one has been found
- At this stage your adblocker will imminently stop working in 3 videos time.
- Personally using Firefox + uBlock Origin and tweaking filters and updates does not even fix it.
Part 3
None of the video loads now, everything looks blank.
- At this stage you must tred new ground to avoid ads. I have posted methods in the comments. If you want to bypass this end page, read down there.
End of Update
YouTube has started rolling out anti-adblock to users inside the United States, which means that they are preparing to roll this out to the entire country. Personally, I have been blocked already. I want to gauge how common this occurrence is.
I reckon that blocking ad blockers isn't some extra countermeasure here. It's actually right in line with what Manifest V3 and that new environment attestation system are all about. They're basically making sure that if you tinker with crucial bits of the JavaScript -- stuff they see as essential (like anti-adblock) -- you won't make it through the attestation and you'll get blocked.
They don't want to block all modifications because that would be a hindrance to many users, for example the visually impaired. However, anything affecting their bottom line will probably be blocked.
Yes, attestation is in line with V3 changes, just that it makes them irrelevant: YouTube's website could some day ask for environment attestation of "no extension using the intercept hooks", or "only the approved ones", and still have the same effect. The fact that they're implementing a server-side anti-adblock now, while postponing V2 deprecation over and over, makes me think the V3 changes are a flop.
Firefox... would likely require Mozilla to play ball and implement similar attestation in an official binary attestable by the OS. Edge too, just so MS doesn't mess with Chrome's binary attestation on Windows.
Safari already has attestation, without extra parameters, but it could be extended:
https://httptoolkit.com/blog/apple-private-access-tokens-attestation/