How are marked cards prevented in Poker?

Question

How would a live poker tournament or cash game prevent me from marking cards using invisible ink or dust, then using custom-made glasses to see my markings when others get those marked cards in subsequent hands?

Answer 1

At a casino, it would be difficult to mark the decks without being seen. In addition, the decks get swapped every few hands, so you would have to mark multiple decks, which increases your likelihood of getting caught.

If you are talking about a private home game, the glasses and your actions would raise suspicions, especially if you won regularly with junk hands, or were the big winner.

Answer 2

There would be

• the ink or dust
• the act of marking the cards
• the custom glasses
• inspecting the cards
• new decks
• dealers and staff trained at detecting
• players detecting
• surveillance cameras
• your actions

In many states you would be breaking the law. In Vegas it would be a felony.

Pretty sure you have not broken poker.

Answer 3

Call me cynical, you could get away with it.

I am constantly amazed by how comfortable and confident that poker players are by their faith in the security systems they believe the casinos have to protect them. I kind of think that it has something to do with the addictive aspect of the game that puts many players in denial about a lot of things, the security of the game perhaps one of the minor things.

Ink and glasses are a little sloppy. You will be in possession of the evidence if caught. You really do not even need to mark the cards. Most are already marked in some intentional or unintentional way. Ace of spades and King of clubs almost always sit on the top or the bottom of a made up deck, tending to give them a little more warp then the rest of the cards. Many card rooms contrary to Herbs contention that the cards are changed every few minutes, leave the same deck in for days, weeks even months. Many card rooms replace a single card in a deck when one is defective or breaks. Kem cards, the most common used cards, have very bad quality control between batches. The cards will vary in thickness, width and height, ink shades and corner radius, all of which make them essentially readable as marked cards. This is a wide spread problem, most card rooms do not care about this particular part of game security enough to spend the extra money to keep the cards in the game in good shape.

A Little Bonus: How to spot a painted deck. Marked decks are typically marked in a pattern. As an example bicycle decks are marked by modifying each spoke of the bicycle wheel on a card back. To spot the marking you look at the deck like you look at a pad of paper you drew a cartoon on. The markings will animate and even the most discrete markings jump right out at you. (somewhere I have a painted deck, I will see if I can get the effect to show up in a video).