[needmorePaine]

Other stadiums have used already existing rooms to sometimes hold unruly fans until police arrive.

Holding cells.

No other NFL team has had the problem to the extent Philadelphia did/does.

An overstatement now. Maybe true in the Vet days. Largely based on repeating the same well-publicized incidents of booing "Santa" and the like. Lately, I've been reading about more incidents coming from places like Chicago and the West coast, and I have experienced a good number in New York and Boston. It happens everywhere when you combine crowds, booze, and grown men acting like thugs (and I'm not even talking about the players!).

[rikkir]

I can only speak to stories I heard from fellow Panther fans, and articles in the Charlotte Observer from the year we went to the Super Bowl.
We had a fan injured enough to need transport to a hospital, and others were pelted with bottles, food, etc.
When opposing team fans come to Charlotte, they might get some ribbing, but they don’t fear for their lives.
That’s been the only reports of such I’ve ever heard from Panther Fans going to any city.
I’m sure some of that happens in other places.
You couldn’t pay me to wear a Yankees Jersey (ever) to a Red Sox game!