 Casinos sometimes take measures to thwart players who they believe pose a threat to them, especially card-counters or hole-card players.However, some casinos tolerate card-counters who do not bet large amounts, who are not good at counting, or who do not use a large betting spread.Some countermeasures include shuffling when the deck is favorable to the player, imposing betting limits, "backing off" players by asking them not to play blackjack any more, or asking a player to leave the casino.