A security method that includes defining rules specifying permitted movements of passengers in a transportation terminal. Passengers entering the terminal may be issued a boarding pass having a Radio Frequency Identification (RFID) tag attached thereto. The location of the RFID tag may be measured and responsive to the measured location of the RFID tag, a violation of at least one of the rules by the passenger may be detected. An action with respect to the detected violation may be taken. The rules may define a region that is forbidden for access, a region in which the passengers are expected to be in motion, a region in which the passengers are expected not to be stationary for more than a given time period, etc.