I witnessed a similar incident a few years ago at the Dearborn Homecoming & commented on it in the "open carry at Arts, Beats, & Eats" thread. This is what I was talking about when I said in an incident like this, if someone had a gun, it would turn into a shooting incident rather than just a fight.

I went to St. Sebastian's festival in Dearborn Heights a couple of weeks ago. They had the midway area roped off with only one entrance/exit station. This station was manned by 2 cops on either side with signs indicating what wasn't allowed to be brought into the area like back packs, water bottles, I can't remember the rest, but it was a list of about 8 different things [[no, pressure cooker wasn't included). There were a good amount of cops patrolling the area too. This is how things have to be now I guess to have a safe festival, you kind of have to have the midway area on lockdown or a quasi-lockdown.