A security tag contains two parts. The contact (or lack thereof) of the two parts defines the operational state of the security tag. In one state, the security tag responds when a central control station runs a wireless security scan. In the other state, the tag does not respond. Thus the wireless security scan reveals the tag's operational state. If, for example, one part of the tag is affixed to a window, and the other part affixed to a flame of the window, then the two parts can be arranged so that they are in contact when the window is closed but not in contact when the window is open. A wireless scan of the tag thus reveals whether or not the window is open. In one embodiment, one part of the security tag includes an RFID circuit, and the other part includes an antenna.