Just for the record, re. real infantry battalions, it is true that in the 1950's the main guard was largely symbolic, in that they went on guard in full parade ground battledress, shining brasses, everything highly polished, which led me always to feel very exposed on barbed wire perimeter guards, marching a few hundred yards repeatedly in full sight of desert eyes. Each man's personal 303 was lined up with the others in the Guard room and taken out on stag , with limited ammo.
HOWEVER, on occasions I have led, in addition to those guards, real business sections, in denims, nothing showing, nothing shiny, surprise packages, targetting those targetting the guard rooms or perimeter wire. Even in England, waitng all night with the guard room under surveillance from a close emptied barrack room, no lights, and armed with a bren gun trained on the main entrance. Unknown to the official guard.
In the desert, I have taken a couple of guards, in similar style, OUTSIDE the perimeter wire, perhaps 100 yards, laying in the sand surrounded by a trip wire.
I guess this was the army looking after itself.