I know, there still videos blocked for NSFW content, where you need to identify you, eg the music video from Harakiri for the Sky - Funeral Dream is flagged as such, but you can still warch it from an other upload, Also not a problem to watch it in Andisearch or SMPlayer. But this filter has nothing to do with the current adblocker problem, age restricted vids in YT are exist since several years.