To everyone who is saying they use adblock and haven't seen this yet: YouTube probably rolled this out to a smaller percentage of users first. It allows them to understand how this change impacts user behaviour, e.g. how many users comply and disable their adblocker, how many more users close YouTube than usual etc. Most tech companies do this type of analysis before releasing a high impact change to all users.
To everyone who is saying they use adblock and haven't seen this yet: YouTube probably rolled this out to a smaller percentage of users first. It allows them to understand how this change impacts user behaviour, e.g. how many users comply and disable their adblocker, how many more users close YouTube than usual etc. Most tech companies do this type of analysis before releasing a high impact change to all users.