Be that as it may, they are in Law Enforcement and they fire warning shots.
Further more, warning shots are:
“The firing of shots or delivery of ordnance by personnel or weapons systems in the vicinity of a person, vessel, or aircraft as a signal to immediately cease activity. Warning shots are one measure to convince a potentially hostile force to withdraw or cease its threatening actions.” (Joint Pub 1-02)”
A private citizen might well desire to signal an aggressor to immediately cease activity or to convince an aggressor to withdraw or cease threatening action.
Of course, in spite of the desires of such a private citizen, doing so is illegal in a lot of places and the private citizen may be subject to arrest for doing so.
They are Law Enforcemennt, and as such, have a completely different set of protocols.
As Law Enforcement, you will never find them or any other LEOs advising private citizens to fire warning shots.