A tamper pool RFID tag apparatus, system and method for keying the RFID tag in association with an object. An oscillator circuit configured on an RFID tag substrate enables the RFID tag to be keyed with respect to the object. One or more capacitors that are operatively connected in association with the RFID tag substrate via a substrate vias determine an oscillator frequency pulse when placed on the object. A comparator compares the oscillator frequency pulse with a predetermined pulse count stored in a latch/storing unit. The RFID tag circuit can accept the object in, for example, a vending machine, if the frequency pulse matches the predetermined pulse count in order to effectively handle object returns in a wide range of commercial applications.