From FreeSpace Wiki
allow-treason Turns the Allow Traitor switch on or off in mission. Takes 0 arguments. 1: True/False.
- Despite what the name suggests, if you want to allow treason, you must set this to false. The "switch" in the description refers to the "No Traitor" option in the Mission Specs Editor (Shift-N) in FRED. It is off (=false) by default.