The present invention discloses a data tag device (100) which initially operates in either an active mode or a semi-active mode (604). The data tag device includes tag circuitry including a interface element (104), a controller element (102), and a memory (106) in which tag data (116) is stored. A battery is provided which is initially coupled to the tag circuitry. A decoupling feature (402) is used to destructively decouple the battery from the tag circuitry when it is desired to disable the data tag device and reduce the ability of third parties to obtain the tag data. The data tag device is configured to detect the destructive decoupling (606, 608), and disable the data tag in response.