If you are a dealer in the casinos, there are some things you are trained to watch out for. Players flocking to the casinos all have hopes to win, and some will try to stack the odds in their favor. Cheating in blackjack is illegal, not to mention the security guys that will muscle you out of the casino.
That hard-working dealer is supposed to be the eagle eyes for the casino. However, in theory, they could be given a bribe to fix a blackjack game. There are a number of tricks a dealer-gone-rogue could employ from tricky mirrors to creative shuffling. I guess the real eagle eyes are those hundreds of cameras hovering above the table to make sure that both dealer and player brought their scruples. Licensed casinos, like those in Vegas and Atlantic City, have too much at stake to cheat their players as they would be shut down by the government.
Marking cards is a pretty low-tech way to keep track of the cards. Players may make an indentation with their fingernails or bend the card in some way. There are fancy inks that are virtually invisible. By marking the cards, the cheater hopes to find out the dealer’s down card. Ouch to the player caught marking cards!
Is that a card in your pocket, or are you just happy to see me? Some magical players attempt to stow an Ace or two up their sleeves for good luck! When the time is right, the cheater will do a quick change-a-roo and swap out the lame 2 of Diamonds for the luscious Ace of Spades. I wonder what happens if the “magician” and the dealer both have the same card? Fireworks!
Some cheats recruit accomplices who will try and take advantage of the dealer. While the dealer looks at the down card, a sleuth behind him will catch a sneak peek and give the player a secret gesture or hand signal. Watch out for new methods being tried out there and protect yourself from those who look to take advantage.