This type of thing isn't exclusive to sports betting, either. Card counting isn't cheating, but is typically prohibited (when executed successfully) in most casinos due to the edge it gives players (which has been practically eliminated with shift to 7 decks, autoshufflers, etc.). When players figure out other edges, such as imperfections in the playing card printing process that gives them an edge in games like baccarat, they'll either get banned or not paid their winnings. It is very much a heads I win, tails you lose situation.
Most strip casinos don't care at all about individual counters. They will cool you though if they see you wonging or other evidence of team play. But an individual? They really don't care. I've counted playing two hands and swinging my bets by a factor of 8 at the Bellagio. I might has well have been wearing a hat that said "Make Counting Great Again" I was so obvious. And the pit boss only asked if I'd like something nicer to drink than the well stuff and my host took very good care of me on the back end. Incidentally I didn't really win much, but that's not why I play. I like the dopamine hit from the risk, I like the sociality of table games, and I like having my host pay for the entire trip thanks to my play. It would make a terrible career, but for a weekend's entertainment it nets out to being a pretty good deal.
Interestingly, if the player doesn't maintain a proper betting strategy, he will have a considerable risk of ruin even in a player advantaged game. In a game with a 10% player edge, 28% of players managed to go bust[1]. Given the large number of rounds of betting for blackjack, without a good betting strategy, even players that count their way to a 2-3% edge are probably still going to make the casino money.
The downtown Casinos are much more uptight about advantage play, but I think that's because a lot of the pit bosses are old school and they just hate the idea of a player supposedly putting one over on them.
I've heard it said that the casinos encourage bad card counters, because someone who has a "system" that doesn't really work for them is going to lose even _more_ money playing. It's only when you start really winning that they care. The fact that you were obvious about it just made it easier for them to identify you once you won anything significant.
The table limits prevent serious losses from card counting. Information has a cost. So long as the maximum bet isn't large enough (relative to the minimum bet), on average even a perfect card counter will lose money.
I've sat at $5 tables where an old dude was openly discussing the count with the dealer. I bet when he bet and made out okay.
Counting theory is really simple stuff. Everyone does it subconsciously. Almost everyone can learn the concept of sampling without substitution. Banning such basic math seems ridiculous, but highlights that the average player is not there to win. Gambling institutions are sad places.
I think almost any card game is going to have some element of card counting unless card counting is completely impossible. It's like trying to play poker while ignoring the psychological elements of the game.
https://en.wikipedia.org/wiki/MIT_Blackjack_Team
https://www.betstrat.com/betstrat-articles/the-phil-ivey-edg...