California Code, Military and Veterans Code - MVC § 326

Commissioned officers, warrant officers and enlisted persons and former commissioned officers, warrant officers and enlisted persons of the United States Army, United States Air Force, United States Navy, or any reserve component thereof, California National Guard, State Guard, California National Guard Reserve, California Defense and Security Corps, California State Guard, California Reserve and Retired List or the active militia, may, with their consent, be detailed for active duty with a security section which the Adjutant General is hereby authorized to maintain in the Adjutant General's office.  A commissioned officer, warrant officer or enlisted person who is detailed for duty as provided in this section may be paid compensation in any grade or rank lower than the person actually holds provided the commissioned officer, warrant officer or enlisted person voluntarily waives all compensation in excess of the lower grade or rank.