Casinos may still ban you even if you are not caught card counting or not doing anything at all. Sportsbooks also do this to players who are just too good at picking odds. I've already read of some players here that were not banned but their account were limited - that means they couldn't bet more. The point is that casinos and bookies do not want anyone to win a lot and empty their vault.
This is not accurate, casinos like having winners from time to time, as it is common for those people to share their stories online and bring customers to try out their casino looking for the same results, so not only they will eventually get their money back but they will make much more money this way, compared to the results they will get if no one ever won, however what casinos do not like are professional players, players that are so good at a particular game they can win consistently, in which case a ban or a limited account often follows, once casinos realize a gambler has that level of skill.
