Some people just really don't know how to read their dogs & think that their dog would never cause trouble. Then when they do the human doesn't know how to respond, thus making it worse usually. I'm glad everything was okay & your boys still had a great day at the park 🙂
I also am a big supporter of dog parks but it's smart to be cautious when taking your pup because you really just cannot predict how other people's dogs are going to react.
Thats also why I usually only take them when I know its going to be quieter with less dogs, you add more dogs then you can add possibility of more issues. I have worked with Reggie everyday since i brought him home, and I can tell just by the look in his eyes, or his body language to how he's going to react to a situation