I've had it happen to me as well. I had two Papillions and would let them off leash in a small park near my house because there was typically never anyone there and they would recall when I asked. We walked there for over a year with barely anyone ever around.

They weren't the problem. Some methed-out looking skid and his trashy gf showed up with some sort of pit-mix. They weren't locals because I had never seen them there before. Their dog barrels over to mine in seconds and proceeds to half maul/half play with them while completely on top of them. Bear in mind, my dogs are 10 lbs soaking wet and his was probably 50. His dog got a couple swift kicks to the ribs before it would piss off and my dogs were completely traumatized.

He finally walks over and I'm irate and he just laughs it off as if his dog didn't practically just kill mine. I totally agree with you but unfortunately some dog owners should never be allowed one to begin with.