In the US, we used to have NFL blackout games. If the football game wasn't soldout, the NFL wouldn't broadcast it on TV. So local businesses or the wealthy would buy the unsold tickets so that us poor peasants could get to see the game on TV. I don't know any games that were actually blacked out since football is so popular and most games get soldout before the season starts. But once in a while news of the potential of a black out game spreads and the unsold tickets get bought up and the game is televised.
Happened to the Raiders in Oakland all the time. Here’s a piece from a couple years ago about how they had to remove seats from sale so they could qualify because nearly every game was blacked out.
> If the football game wasn't soldout, the NFL wouldn't broadcast it on TV
You’re missing a key part of this. It’s only “blacked out” in the local market of the home team.
If the Cowboys are playing in Jacksonville, you better believe that game is going to be on TV in Dallas (and possibly most of the rest of the country) no matter how many tickets get sold in Jacksonville.
That said, blackouts are very rare and AFAIK no game has been blacked out in about 5 years.