Its extending respect to. Most families has or had a family member, friend who has joined the military and has deployed around the world. According the Army Regulation, courtesy visits have to be done unless there are unforeseen circumstances that permit the visit. To the untrained eye there does not seem to be too many variations between the civilian world and the military world besides the evident like uniforms, stricter standards of living, and traveling.
According to Field Manual But one thing they all have in common is they show the respect and honor the soldiers and their superiors have for one another.
Paragraph When swearing a loyalty oath, what will soldiers do with official events, social events and sports events? When talking to an NCO, you always finish your sentence with his or her rank. The salute on the part of the subordinate is not intended in any way as an act of degradation or a mark of inferiority, but is simply a military courtesy that is as binding on the officer as it is on the private, and just as the enlisted man is required to salute the officer first, so is the officer required to salute his superiors first.
Signs of military discipline are displayed in a number of ways. Becoming intoxicated while in uniform will not be tolerated. Having all of that insures sufficient military leadership.
However, to the trained eye one huge difference stands out.