Liquid Chips said:
In land-based casinos, how often to dealers cheat? Is there any training courses on how to spot cheating dealers?
I agree with everyone that it's quite unlikely.
One method of cheating is to short the shoe. Remove tens and aces. Less commonly (because it's easier to detect) is adding low cards.
Another is to deal seconds (the second card). If the top card is favorable, they deal it, otherwise blindly deal the second card. This requires either a marked deck, or peeking at the top card on the deck. The best way to catch peeking is by watching the dealer's eyes. If they check their watch a lot, they may be peeking.
Dealers who deal seconds may have a slightly different sound when they deal. More swishy instead of snappy. However, they will usually have a more pronounced dealing motion, so it won't be easy to spot. In fact, in all likelihood, you'd never be able to even see a second being dealt. Your best bet to catch them is to see the peak, or marked card. Or just don't play with dealers who have a flashy dealing motion that would allow them to cheat (I've left the table before over this, although I freely admit I was being paranoid.)
Another way to cheat is selectively flipping an upcard, or switching the hole card. If the dealer doesn't always flip the same card, they're probably cheating.
Another way is to control clumps of high cards and keep them at the bottom of the deck. They'll need to do false shuffles and probably be able to undo a cut in order to pull this off.
Another way is through stacked decks. Again, this can be done by using false shuffles and controlling the discards. They'll do weird things with the discards, or during the shuffle, or have marked cards in order to do this.
You can also stack the deck, or deal seconds, by shaving certain cards. For example, if the non-tens are shaved, then tens stick out a bit. Highly unlikely because it can be spotted, and provides physical evidence.
Lastly, there's preferential shuffling, which while considered legal by some idiot court, is most certainly cheating in my opinion. This involves shuffling away high counts and dealing deeply into low counts.