"The Resolution Procedures Manual is one of five security reference handbooks providing background information, guidelines and procedures regarding passenger questioning and resolutions in conjunction with the Dupe Checklist (DCS) Program. It is intended to be used for operational guidance and/or training activities. A passenger may be duped into carrying a bomb on board an aircraft under the following circumstances: (1) A bomb is placed in an unsuspecting passenger's unattended baggage; (2) An unsuspecting passenger is given a bag to transport on his/her flight. A bomb is concealed inside the bag; (3) An unsuspecting passenger is given an item or a package to transport on his/ her flight. The item/package contains a bomb: (4) An unsuspecting passenger is given a 'gift' just prior to the flight. The gift contains a bomb; (5) A passenger may believe that he/she is involved in some type of illegal activity. Such a passenger may believe that his/her bag contains contraband (e.g. drugs, gold, cash, or diamonds). The passenger is not aware of the true contents of his/her bag (a bomb); (6) A passenger who is a terrorist, or a terrorist group sympathizer, may believe he/she is transferring confidential material or an explosive to his/her destination. In reality the passenger is carrying a bomb setup to go off on his/her flight."
Defense Technical Information Center (DTIC): http://www.dtic.mil/dtic/