I've been to about 2 or 3 dog parks, all in the Northern VA area.
They are generally well kept parks, and I see a lot of breeds come in and out of there, and there are no breed restrictions, which is the way it should be.

What you can do is find out who owns and helps run this dog park and speak to them your concerns about this breed ban!

I have seen some pit breeds come in, and see some other owners grab their dogs and immediately walk out.
I've seen several rowdyness and fights, but NEVER from any pit looking breed.
I frankly LOVE pits and really hope to own one someday, I have a soft spot for them as one of my fav breeds.

-Scoop your poop, and any that someone ELSE didn't bother to pick up.
-ALWAYS keep your eye on your dog(s)
- Always have the leash on your body
- No dogs that are aggressive PERIOD, even if they are onleash, some other dogs can since anothers attitude, or hear growling, and it can send a large pack of dogs into a big frenzy towards other dogs. Some dogs feel uneasy onleash while all others are offleash, and act out. And some other dogs will pick on dogs whom are ON leash.
- I think it's great to have a trained dog, I wish all owners would be this responcible. But I do understand that there are just some dogs that will not 100% reliably come to you when you call them, while they are offleash outdoors. Shiba Inu's specifically are notorious for this!
- An owner needs to be able to take control of their dog in any situation.
- Water guns are stupid when dogs start fighting! It waist time, while another animal gets injured.

My last foster was attacked by 2 dogs, a GP/BC mix, and a rottie (and the rottie's owner had said just a moment sooner, oh, he'd never hurt anyone.)
There was also some ugly Irish Setter mix, HUGE, a good 180 pounds easily. He started 3 fights before his owners finally left, actually the rest of us MADE them leave. And on all occasions the owners just stood in a corner not doing anything about their dog fighting. After ripping open one dogs side, it went for a black lab and bit a chunk out from under it's eye, my fiance had to reach down and grab the Irish SetterX by the neck and litterally lift it up and off of the other dog, cause no one else there could do anything to help the lab, let alone strong enough to do anything about it (another perfect example of bringing dogs you LITTERALLY can not control in any situation)!

My fiance had to hold the dog like this (very aggresive dog) until it's owners finally decided to saunter over, everyone formed a circle around this dog to help prevent him from attacking again.

I don't think it's the pit breeds we need to be worrying about.