WHEN MUST YOU TURN IT ON?

Failing to activate a BWV raises serious issues with the Police Commission.  What are you trying to hide, is their unspoken suspicion.  Therefore, the Department pays close attention to failures to activate.
The BWV policy is explicit.  Section III of Special Order 12, April 28, 2015, says this (my emphasis).
“Officers shall activate their BWV devices prior to initiating any investigative or enforcement activity involving a member of the public, including all:
• Vehicle stops;
• Pedestrian stops (including officer-initiated consensual encounters);
• Calls for service:
• Code 3 responses (including vehicle pursuits) regardless of whether the vehicle
is equipped with In-Car Video equipment;
• Foot pursuits;
• Searches;
• Arrests;
• Uses of force;
• ln-custody transports;
• Witness and victim interviews (except as specified below);
• Crowd management and control involving enforcement or investigative
contacts: and,
• Other investigative or enforcement activities where, in the officer’s judgment,
a video recording would assist in the investigation or prosecution of a crime or
when a recording of an encounter would assist in documenting the incident for
later investigation or review.”
There are, however exceptions.  See section VI.  Emphasis is mine.
Exceptions: Officers are not required to activate and record investigative or enforcement encounters with the public when:
• A witness or victim refuses to provide a statement if recorded and the
encounter is non-confrontational:
• In the officer’s judgment, a recording would interfere with his or her ability to conduct an investigation, or may be inappropriate, because of the victim or witness’s physical condition, emotional state, age. or other sensitive circumstances (e.g., a victim of rape, incest, or other form of sexual assault)
• Situations where recording would risk the safety of a confidential informant citizen informant, or undercover officer; or
• In patient-care areas of a hospital, rape treatment center, or other healthcare facility unless an enforcement action is taken in these areas.”