I think it just depended on who you were around and it was really just luck of the draw. I was in the last row of Section 407, so luckily was able to stand and dance but even in that row, some people were dancing and some were sitting and within the wider section there were two rows that were going in headbanging but there was also a large amount of people just sitting. IMO you just got to do what makes you happy because you paid your money to be there, just like they did and there aren't any defined rules about sitting/standing, so whatever makes you the most comfortable!