The satellite feed that's licensed for public venues has a small beer glass logo burned in to the image. The amount of beer in the glass changes every day on a pseudorandom basis. An inspector can check whether a pub has the right license simply by looking at the screen - if the glass is missing or contains the wrong amount of beer, it's an unlicensed stream. It's plausibly hackable by a sufficiently motivated person, but it's a remarkably simple and effective deterrent.
https://mindyourdecisions.com/blog/2016/12/13/game-theory-ap...