eli5 how do casinos determine if someone is counting cards?

Question

eli5 how do casinos determine if someone is counting cards?

In: 59

Answer 1

In some games such as Blackjack, particular playing strategies may indicate that someone is paying close attention to the cards that have been dealt

For example, a player who plays a few hands at minimum bet, and then raising their bet dramatically a few hands into a particular shoe only return to minimum the next time the shoe is shuffled, could be a card counter..

Some playing strategy deviations could also be suspect. For example, splitting a pair of 10s against a weak dealer up card, or taking insurance bets often becomes profitable if the shoe is very rich in 10-valued cards.