Card counting, while not illegal, can get your thrown out of a casino. But it is quite useful when it comes to blackjack strategy. But to pull it off well you have to practice it, and even then you have to be careful when counting cards at the blackjack table so that the dealer or pit personnel are not tipped off as to what you are doing.
Typically this means keeping the spread of your wagering small, and perhaps now and then throwing in a variance in your wagering, such as betting less when you should bet more or vice versa. The point is that you would be using it as a distraction. But I heard of another distraction that was used to cover up card counting.
I heard the story of man who was playing blackjack in Vegas and counting cards. So was the other guy who was at the table with him. Naturally since they were both counting and they were the only ones at the table, they were keeping their spreads small. But then a pretty woman stumbled up to the table who appeared to know the other guy. What then ensued was the other player giving her some of his chips and inviting her to play with them. But she was a terrible and sloppy player; even if she had not been drinking it was doubtful that she would have done well.
The other player helper the woman with her blackjack playing as best he could. Then the dealer, taking pity, started to give her tips and try to help. Finally pit personnel wound up trying to give her pointers to help her. While all of this was going on the other guy and the guy who told this story had increased the spread of their wagering. As a result the other man wound up cashing out for $30,000.
This is a case of distraction at the blackjack table. The dealer and pit personnel were too focused on helping the tipsy woman with her poor blackjack playing that they did not notice the two men increasing their spreads and making more off of their card counting.
While many blackjack players will resort to some sort of distraction to keep casino staff from picking up that they are counting cards, I had not heard of such an elaborate distraction. And while some distractions work at the blackjack table, they are not meant to replace skill and practice in card counting.