Was it one of the wireless shock collar types? They are not really a barrier. Beside failing to work on occasion even if they do what they are supposed to it's only a being persuasive. I tried one on myself on the highest setting and while it hurt it wouldn't keep me from passing the wire if I really wanted to.
Some states (Texas comes to mind) you can be held criminally responsible if your dog attacks. South Carolina says the dog has to be a "dangerous animal" and defines that term clearly and states "An animal is not a "dangerous animal" solely by virtue of its breed or species."
