That makes me so angry when kids do that! I spent so much time teaching my kid to be savvy around dogs. Don't pet strange dogs, don't touch dogs that are sleeping/eating, don't put your face near a dog's face. And fat parents always assume that because my dog is so well behaved that my 3 year old can walk him that he likes kids. Well, he doesn't. He likes MY kids, but in his opinion other kids can fuck off. I always yell "my dog bites" now. Its actually really funny to watch their reactions, especially since they are usually pretty far behind their kids on the path, and immediately break into this alarmed, shamble of a run to get their kid. (My dog would never bite, but they don't know that.)