A radio frequency identification (RFID) tag comprises RFID circuitry, an antenna,
and a detector responsive to electromagnetic radiation of a predetermined frequency
and for controlling cooperation between the RFID circuitry and the antenna when
electromagnetic radiation of the predetermined frequency is detected. The detector
may be responsive to light of the predetermined frequency to enable cooperation
between the RFID circuitry and the antenna when light of the predetermined frequency
is detected. Alternatively, the detector may be responsive to light of the predetermined
frequency to disable cooperation between the RFID circuitry and the antenna when
light of the predetermined frequency is detected.