This is very old technique and these days you can not make big money with this. House will catch you and will ban you from their casino. Even you will end up beaten by them badly.
If someone beats you up because are card counting then you can pursue legal actions because card counting is legal and it is a subjective thing. That is why I said in my post that someone might be having a lucky day.
For online we don't see that, and then there's the element of RNG (random) that is on their side. They can shuffle every x deal, or not. So I don't think the card counting will be effective in online games.
If you know how many decks there is in the shoe, you can see if you will be winning. There is no RNG in blackjack because there is a fixed number of cards in the deck maybe the chances are what you are talking about. It is unfair for people to just kick you out or ban you because you are winning.