Yes terrible, our mini collie nearly bled to death after being mauled by two staffies. Both our dogs have been bitten multiple times in dog parks. I complained to council, the Victorian state dangerous dog register - nothing ever happened. And you can't control rude crazy humans bringing untrained vicious dogs into public spaces sadly.
Now we all avoid dog parks as it only takes one crazy person to bring their a single vicious dog into an enclosed space (Council Dog Park) and all hell breaks loose...kids are traumatised,dogs injured, adults all screaming at one another...suburban peace ruined:-(
We have 6 dog parks within 20 mins drive here and 2 very active Collies...no chance we will take them into one again.We just have to go very early in the morning or late at night and let them run about in an open space with either no other dogs or the dogs of our carefully selected friends.