as an ex-mil and having lived outside the US for years, all my digital devices with time-keeping run on the 24hr system. I normally switch the OS to use YYYYMMDD or DD.MM.YYYY. For abbreviated writing, I often use the DTG method as well, (Date Time Group). The habit of the civilian US to use Month-Day-Year just makes life difficult, expecially for programmers that have to parse date field entries into useful numbers.
And yes, it is 0012, not 2412. or, as we used during a boring mid-shift, Oh-dark-thirty or whatever the minutes happened to be on. Otherwise the digits were always individually specified, such as zero zero three zero to avoid confusion during unpleasantries. No, I never use a colon between the hours and minutes.
There was one situation I experienced where the time was routinely "adjusted". Once upon a long time ago, I happened to work a couple years in the USFS in northern Idaho - big timber country. Whenever we went out on a fire, if I was not on the fire line at night and was actually in my paper sleeping bag in the main fire camp, at about 0430 the fire or straw boss would walk around the camp saying very loudly: "Day, Day, Daylight in the swamp". and repeat it until everyone was up. The analogy was that in the deep swamp bayous of Lousiana down under the tree canopy, it was so dark that the sun could have risen and you would not know it. Why were we rousted out to the fire line at that time of day? Under normal conditions the diurnal mountain winds switched directions somewhere between 0530-0700. Hence with little/no wind the fire calmed down and we could get some hotlines down to mineral soil right next to the burn. Unless of course there were widow-makers above us, in which case the chain saw crew fired up their saws and dropped whatever trees were bothersome while one of us watched above to see what was coming loose. A widow-maker is a partially burned thru branch waiting for any disturbance to drop on the unsuspecting below