A few years ago, I was walking from Parra stadium back to the train station with my now wife, along with the thousands of other people who had just been to the Parra-Bulldogs game.
That's the only time I've been to Parra stadium, so I don't know the area that well, but we were walking down the main street, before the paved mall part starts, and there were a number of restaurants with outdoor seating. It was a Friday night so there were quite a few diners. I felt sorry for them because they were going to have to put up with the hordes of football fans chanting and yelling as they walked through.
Unfortunately, there were a number of tools who saw the situation as an invitation to start running through the the crowd knocking diners plates off their tables and flipping plates over etc. Fortunately, the police weren't far away and managed to catch up with at least one of the tools.
Having witnessed that first hand, I have no reason to believe that what Shire Panther has described didn't happen. It sounds all too familiar.
I don't know what happened to those that the police managed to nab, but my guess is that it wasn't much. That's why I think big fines are the only deterrent.
Regardless of whether it's drunken idiots causing trouble, or these gangs of idiots causing trouble, there needs to be an effective deterrent.