It has been a while, Hell, it’s been a long, long while, but my recollection that hand salutes were not required or encouraged indoors with one big exception. You saluted when reporting for duty. There was even a script for this: “Sir, Lieutenant Gelding reports for duty as ordered.”
It doesn’t always work that way.
When I reported to my first duty station, Fort Lost in the Woods, Missouri, I went to the Executive Officers office and started to go into the mandated spiel, but it went like this:
SG: Sir, Lieutenant Geld…
XO: Sit down son. Glad to have you with us, Spav. People do call you Spav, don’t they?
SG: Sir, Lieutenant Gelding reports…
XO: Son, I know who you are. I know why you’re here. Now sit down. (Shouting into the next office) Bob, the new guy is here.
Both the XO and the Staff Judge Advocate, a lieutenant-colonel and a full bull, were WWII veterans (the XO had carried a BAR from one end of Italy to the other and the SJA had jumped on D-Day and at Arnheim) and both had been on continuous active duty since Korea. That, and the fact that it was a staff section of lawyers, may have had something to do with the surprising informality of my reception.
Also, the hat comes of indoors, especially in mess halls where the mess steward will politely ask you to uncover if you forgot. The exception to the uncover rule is when under arms.
The old general rule was to figure obvious officers in other services, including foreign services, received military courtesies. So did foreign countries’ national anthems and national flags when passing in review.
Let me emphasize one thing civilians forget or do not know. The hand salute is not a gesture of subordination. It is simply a courtesy. The failure to give that curtsey is rude. I have watched an army captain get a lecture at the hands of a brigadier general for failing to return a salute from an enlisted man.
Carry on. I’ll be in the area all day.