I'll give my answer by telling a little story...
When I was in the USAF Strategic Air Command, portions of our bases were even more secure than others, and were designated "No Lone Zones."
In those areas a single individual was considered a security threat, would be challenged, and if they did not immediately stop, WOULD be fired on.
While I was stationed at Carswell AFB, TX my squadron commander (a B52F pilot) was returning to the alert shack after a practice alert and realized he had left his flight bag, with his codes, on the aircraft.
When he dropped his crew off at the shack, outside the Alert Area, instead of parking the truck, Colonel Hooker turned it around and headed back to that nuclear loaded alert aircraft to recover his bag and codes.
He single mindedly wanted to get those codes back in his control.
He buzzed right by the rookie A2C guard at the gate to the Alert Area, and didn't even hear the challenge yelled at him.
That young guard put three .30 cal rounds through the back of the USAF crew-cab Dodge, blowing seat stuffing all over the cab, putting holes in the dash, and getting Col. Hooker's undivided attention.
Hooker stopped the truck and sat there as the guard ran toward the truck while on his radio 'sounding the alarm.'
Almost instantly Air Police trucks had Hooker surrounded and on the ground in the rain, and he rode in the bed of an AP pickup, with two guards covering him, to the base lockup.
Had my Colonel not stopped his truck, that guard would have definitely stopped my Colonel.
Two weeks later Hooker was out of the USAF and the guard was promoted and honored.
Yes, there are areas where it really is shoot first, no questions.
(That was 1968.)