A method or system to, in response to automatic shuffling of a set of cards by a shuffler, detect a first anomaly of a first card of high value that was used during a round of play for a first card game in which a first player participated at a gaming table. The method or system is further to, in response to analysis of shuffler data, detect a relationship between the first anomaly and a second anomaly. The second anomaly is associated with a second card of high value that was used during a round of play for a second card game in which a second player participated. The system or method is further to, in response to detection of the relationship between the first anomaly and the second anomaly, relate via a collusion-confidence score a first identifier for the first player with a second identifier for the second player.