There's a huge park near our house that's kind of the neighborhood "off-leash but technically on-leash" park for dog owners around here, and I definitely know what you mean about being peeved at people whose dogs really have no business being off leash. Someone whose dog is aggressive to the point of being scary or unpredictable shouldn't have it off-leash; someone whose dog ignores recalls shouldn't have it off-leash either. Someone whose dog is both needs to do some serious TRAINING so that the dog isn't a menace to people obeying the leash rules!

We scan the park very well before letting Kobie and Eli off-leash: lots of other dogs, or even an unfamiliar dog around, and we don't go. We keep very close tabs on Kobie while she plays because she's the one still learning to be friendly to other dogs, but her recall is perfect because we've trained it. It can be done, and people who stand around hollering "come!" at their totally oblivious dog usually get a talking-to by myself or the hub. I hate it when my dogs are polite and obedient, but some idjit has uncontrollable beasts running loose!