As a teacher, I was confronted with a parent who did not want their child to stand or say the pledge. I just told them, "I ask the children to stand. There is no 'Will you?' to it." I don't mind if they don't cover their heart or say the pledge.. but when I give a direction, they are to obey just as I tell them it's time to line up for home. " Respecting authority should begin at home and continue in school.
Anyone athlete who is fortunate enough to be in this country and reap the rewards of a capitalistic, free country should show respect and at the very least stand to honor those who died to make this country free.
I personally feel, however that anyone who does not respect this country and flag should hop on the next flight to a country they could respect. Let them then find a career that rewards them with millions for catching a ball.