And it is easy to see why that is the case, if you win big in slots as long as you did not cheated the system in some way or form then you just got lucky and as such there is no reason for any casino to do anything, because as long as you keep gambling sooner or later they will recover that money from you due to the house edge, but this is different when we are talking about sports bets, because even if there is a house edge it can be overcome with expert play, so someone which is an expert at a particular sport could drain their coffers without any ability for the casino to get their money back.
Well you're right, for slot games it's impossible to cheat unless he's a dev team from the provider I've seen cases like this
The most common is in sports betting because it is very possible for gamblers to make deals with athletes/players to determine the final result
If the casinos don't realize it, their funds will continue to be drained this is the most common case.
In order to win at sports bets it is not necessary to do something that extreme, the house edge changes depending on the matches and the specific bets you are making, but it can be overcome if you can predict which team is going to win at a percentage slightly higher than 50%, and while this will not guarantee that you will win all the time, if you have a good money management strategy then you could eventually get profits over the casinos.