Comment by kaelinl

This, in turn, will spawn user scripts which work around the detection. Any client-side solution will be an arms race between Google and user script/adblock devs. The only real way to prevent it is to withhold the video stream from the CDN until the client has streamed the full ad and/or bake it into the video stream. My impression is that Twitch does this for its live streams (although not VODs).