I highly doubt card counting is easier in online casinos (unless you are playing blackjack online with live dealers). In fact, its easier to do in physical casino and there is nothing much the house can do to stop it other than telling you to leave the table ( I don't think they call the police for such matter, since if I am not wrong, counting card is not illegal). They do take measures, but most casinos avoid those extra precautions you have mentioned since the games ends up being really slow. If you keep on winning or act suspicious, put you under surveillance. It's easier to avoid all those hassles in online casinos because everything is automated. Shuffling cards after each and every hands with multiple decks just takes few milliseconds!