An interesting perspective I read: A former army officer and five other army buddies who were trump protestors managed to get into trump's Tulsa rally. (They were there to raise a flag.) When the national anthem started playing, his group was on the concourse. They immediately stood at attention and saluted. As they stood there, he said not one other person stopped what they were doing. They continued buying drinks, walking, drinking, talking, hats on, etc. Some would look at these folks who were saluting (who were not obviously dressed as army officers) and seemed embarrassed but still did nothing. Finally, a couple of folks stopped, took off their hats, and stood still, but not until almost the end of the song.
FWIW, play the home team's song or something and get the game underway. Skip the anthem entirely.