Thought about this since the Trillbillies brought it up briefly on their latest podcast. I haven't been to too many sporting events in recent years but I typically do what Tonya does and just try to avoid being in the stands when the anthem plays. But I'll admit I'd probably be a coward in most situations and just stand anyway. At least if I'm there with other people. I feel like most Americans are afraid of confronting people but one exception is if people feel you're not showing proper respect to the civic religion or to the troops.
That said if I was at a sporting event by myself I'd probably just sit.
I just think it's fucked up how there is an expectation that at every sporting event US Americans are just expected to stand for the anthem and if you don't hooo boy you must be trouble.
i treat it like a commercial break. last time i went to a big thing (major college basketball game), i just sat there and kept chatting with the person i was with. granted, i was clearly the oldest, hairiest, and frumpiest person in the seating area, which grants a little leeway in social situations if i don't make a scene.
also, one of my philosophies in life is "don't stand when you can sit."