Shuffle Master acquired a few patents for RFID poker chips in 2005. Before and since, casinos and chip manufacturers have put into play various security measures on their chips to prevent the use of counterfeit chips and to track their movement.

Unlike counterfeiting measures used in currency, used only to prevent their illegal manufacture and distribution, counterfeiting and tracking technology in poker chips are used to track every chip antied onto the table to prevent players from surreptitiously adding or withdrawing chips from their bets after they’ve seen their cards.

If that weren’t enough, RFID tracking in poker chips is also used to track the gambling patterns of each player. Allegedly to determine if they are betting against “what would be expected” given the RFID-tracked cards they have been dealt, but clearly for other purposes, as well.

(source)