Unfortunatly we had a similar encounter the other weekend. We had just started taking ours to the park near us, they loved it, able to run around and play with other dogs, we though, great every weekend we'll bring them and let them have fun and meet all the dogs and become more socialized.
Well we went the other weekend and as we let them in, noticed that a couple had a small 7 mth puppy in the big dog area as well as another lady had a spaniel and a small poodle probibly under 10 lbs. I kept a close eye on ours as they are all 65 lb'ish, and kept thinking why don't you take your dogs to the other side that is set up just for small dogs or puppies.
Well, the little poodle goes and snaps at our little girl, she snaps back and goes to push her down as she does with her two brothers. Our other two come over to make sure there little sister isn't getting hurt as well as a few other big dogs, a scuffle starts. We get them all seperated.
Lady picks up her dogs, goes outside the park, comes back and yells that one of us in here has a vicious dog as her small poodle has a small scratch and is bleeding.
Duh, that is why they have two sides to the park, even if they didn't get into the scuffel, I was worried that one of mine was going to step on the small dog and hurt it.
So because I have three hunting dogs, that had been good with all of the other big dogs , loved to run with a great dane that was there and pal around with a huge german shepard, my husband say's that we cant go back because someone might do that again and doesn't want to risk one of ours getting snappy or in a scuffle with a small dog.
So just a rant because people can't read signs and follow directions and let your dog run around it the right area for it's size, our dog's are now religated to run in the back yard or go for walks.