My brother and I still talk about coming back from overseas and being surprised & disappointed when the movie theater didn’t play the anthem before the trailers.
I have kind of a funny story related to that.
Poltergeist came out in 1982, and I went to see it in a theater with a bunch of friends. Now, the movie starts out with a completely black screen, so the theater is pitch black. And long before anything shows up on the screen when the movie starts, this beautiful version of the national anthem begins at a pretty good volume.
Now, I grew up as a military brat, and had just got out of the navy a couple of years before, and my muscles started twitching.
On the bases I lived and served at, they began every movie by playing the national anthem and everyone in the theater would stand up. So here I was, completely baffled, having never done this in a civilian theater, and my knees kept trying to involuntarily straighten out and bring me to my feet!
I eventually stood up straight, and when the screen lit up, and I could see nobody else was rising, and at that point I realized it was part of the movie...:) I am certain people would have looked at me like I was some kind of weirdo...