[Terry]

Surveillance operators don't often look at the index, they read the pattern of the spots on the cards. It doesn't take much time watching games on monitors to also learn to distinguish the face cards by their patterns.

Note that on Blackjack games, the dealers always arrange the players' cards so the center spot is showing; that allows surveillance and the floor people to read the cards from a distance.

And by the way, the cameras in casinos can zoom in close enough to count the hairs on your knuckles.