Blackjack dealers and casinos use a combination of observation, surveillance, and behavioral analysis to detect card counters. Dealers are trained to notice fluctuations in bet size and player behavior, particularly if a player consistently increases their bets when the deck is favorable. Casinos also employ advanced surveillance systems with cameras and facial recognition software to track players and identify suspicious betting patterns. Pit bosses and floor supervisors keep an eye on table action and can communicate discreetly with dealers if they suspect a player is counting cards. Additionally, casinos may adjust game conditions, such as shuffling more frequently or using continuous shuffling machines, to prevent counters from gaining an advantage. Player tracking systems also help by recording betting behavior, making it easier to spot patterns typical of card counting.