Broadcasters also keep logs of their broadcasts for verification purposes. The traffic systems that inject the ads have parameters for how often and what times certain ads are played which are quite deterministic.

For the World Cup, this was always easy.

It was not easy for your local triple A baseball game being streamed to 500 viewers. This approach scales down.

Hours of bleeding-edge CV analysis sounds pretty expensive for a triple-A game streamed to 500 pairs of eyeballs. They’ll be using the pen & paper approach, too.

Not at scale - a thousand games automatically scored: easy, just feed in the new video files. A thousand workers for individual matches across the country and different channels: absolutely not.

Not to mention human accuracy will likely be way, way worse, no human being will maintain their attention counting ads at five second intervals for even ten minutes, almost two hours is unthinkable.

If attention is all you have, humans are pretty bad at it for long boring tasks.