Interesting article at:
http://nba.fanhouse.com/2009/11/25/roys-anthem-absence-draws-attention/
"Before every single NBA game, both teams line up at their respective ends of the court while the national anthem is performed live. It's a ritual that we've become so accustomed to seeing, that we're not exactly doing a roster check or a headcount to make sure that every player from each team is participating. If we did, then we'd notice the conspicuous absence of Brandon Roy from the festivities." (Click the link above to read the whole article)