Your dogs running loose away from you are not valuable as a protector. Untrained dogs are useless, too. Beware of men who approach and just about the first words out of their mouth is "Does the dog bite?" Your answer is ALWAYS 'Yes'.
So true, and I’ll add that training your dog is an on going time consuming process. I highly recommend good working clubs or training groups for anyone even thinking of doing protection work. Some dogs will protect, other’s will not, I‘ve seen many, even long-time dog owners, misread a dog actually showing fear rather than protective instincts. In today’s society a rock solid genetic temperament and rock solid obedience training is needed before even thinking about doing protection work. Having a dog with impeccable manners and obedience will make most potential trouble makers wonder just how much more that dog might really know!
What most dogs will do is give you advanced warning and that alone is valuable.