Some of the casinos use RFID tags inside their chips. One time I sat at a black jack table and after everyone placed there bets in the betting area, the dealer would press a button with a light. If it turns green she proceeds and deals the cards. I have never seen it turn any other color. When I asked her what it was all about, she explain the RFID tags in the chips. And for those familiar with a black jack table, this was NOT the small black triangle mounted on the table in front of the dealer that reads the cards and tells if a dealer has a 21. This was a separate device, mounted on the side of the table ans scanned the betting area in front of each player.
On a side note, I worked in the security industry in 2000 and was intimately familiar with RFID cards and access systems. One of our tricks was to take apart the system badges, remove the copper spool and chip and ball it up and stick it in our clothes or shoes or whatever. To open a door all we would do is wave that object/bodypart/whatever in front of the reader and open the door. We entertain easily. The point is that the equipment was capable and cheap in 2000, it can only have gotten much more sophisticated since then.