I still say the the solution is simply to play the anthem while both teams are still in the locker room, and make it league policy.  In the locker room, players can stand, sit, lie down, or do whatever they want.  The problem is that the national anthem is televised for whatever reason, and of course, there are thousands of fans watching live.  Take away the television and live audience.  Nowadays, it seems like it's always "Look at ME!"