Dockermus;
Let's try to remember that it began with an over-exited, possibly aggressive, supporter choosing to loudly call out a follicly challenged umpire as a "bald headed flog".
You have hit the nail on the head, the trouble started when the Carlton fan was "over-exited" by security staff.
Had he just been spoken to, and asked to respect the umpy, and those around him, in the second half none of this idiocy would have occurred.
As for the AFL, they try to control the crowd off the field the same way they control the game on the field, by over reacting in a huge way to every little incident that occurs, not taking a breath and considering what might happen as a result of their reactions.