It's a little bit of column A and column B. Sure, kids should know to keep their distance from unfamiliar animals but at the same time we do have dog owners out there who take the notion of leashing their dog as some kind of insult. (Most) Dogs don't just sit in the corner and watch. If they see something that peaks their interest even slightly they're going to go towards it and that interesting thing might just happen to be a scared kid. I won't blame a dog or the owner for getting defensive if a kid runs toward them but I will blame them if they don't leash their dog and that dog proceeds to invade everyone else's space, including that of people and other dogs.