I quit going. Have had several negative encounters; a couple drew blood and the last one only the fur flew, but that was enough for me.
I had approached the owners and said that I thought their dog(s) were being aggressive not only with my dog, but with others. They seemed put off by my comments. Only when their dog attacked another dog or my dog did they sheepishly decide to remove their dog(s) from the park.
Maybe my approach was poor, but whatever the reason, I was not able to provide a safe environment for my dog, so I left.
One time a couple carried their Spaniel out of the park because it couldn't walk after a thorough beating. It was conscious, but was as limp as a noodle and matted with blood. As far as I know, it didn't die and is fine now, but there was no recourse. If an aggressive dog attacks another dog like that, you are on your own. The attacking dog probably got banned. I was also told second-hand that the owner of the attacking dog didn't pay the vet bills.
Maybe the owner didn't pursue it with a lawyer, but who wants to spend many hundreds of dollars to maybe win a settlement that you probably will never see? Not to mention the further victimization of going to court on top of the incident at the park?
Even a Rottweiler can get an eye torn out as easily as a smaller dog. I've seen a Karelian Bear Dog, an experienced, trained bear confrontation dog, get its leg broken in a dog park. If a dog like that can get hurt, most any dog can.
Not my idea of fun.