I highly doubt the RFID, active or passive. I would guess that the casino will now remove all remaining chips of the stolen denominations, and replace them with a completely different design/color that way, if an old one shows up, its acquisition can be questioned.
They won't remove all remaining chips of stolen denomination (too much involved...... i.e. gaming commision, design and production cost). Just easier to track and keep alert for stolen ones. You can't just walk up to cage and cash out big denomination chips, ID's are checked and verified, etc., etc.