I have taken mine to a couple of dog parks. We had positive and not so positive times. We've met up with Brister from time to time.
And like she said, most of the people follow the rules. Now having said that, the last time we were at my local park, I was very dissappointed in that there was obviously some people who did not clean up after their dogs! That is just rude and unnecessary but it had only been that 1 time that I can say it was like that.
There was another time that there was a larger dog in the small dog area but she said that the others had invited her in there, but I felt that as more people arrived, she should have excused herself and her larger dog. My poor Maggie May was scared of the dog as that dog kept barking at her. I had met up with some friends and fortunately their dog kinda protected Maggie from that dog. We didn't stay very long that day. So you just have to be aware that there may be some times that may not go as planned but overall I enjoy taking them to the park as they enjoy running around.
Just keep at good eye out at all times.