When I was in first grade at Ocean View Elementary in California, we said the Pledge of Allegiance in class every morning. In my last 20 years of teaching, there was only one school year that we did either the Star Spangled Banner or the Pledge of Allegiance.
When my husband was in the Army, they played the Star Spangled Banner before every film at the base theater. Enlisted men and their families stood outside until it was over; officers sat and stood and put the hand over the heart. I think officers were setting an example. I don't know why we'd rather stand outside rather than get up for a few minutes inside - except that you could socialize/smoke/drink outside.
I figure that since the government doesn't financially support the NFL, the government doesn't need to be honored during professional football games- As for high-schoool sporting events, I don't see why high-school athletes should honor a government that is trying to give them a bad education.
Just a Missouri school teacher ... stubborn as a mule and addicted to logic.