That’s how we did it on base (USAF) when I was a kid.
Living overseas on US military bases, retreat was done to the bugle call "To The Colors" not to the national anthem.
We returned home when I was 16, I heard the "Star Spangled Banner" at retreat and cried like a baby.
I remember that feeling every time I hear about the nfl prima donas taking a knee and pity them for never knowing how good it is the live here.