Read about the UK Kennel Club's shock collar campaign here.
It does make me ask the question though if the end justifies the means. If it saves a family dog from getting run over because it learns (very quickly I imagine) to stay within a certain perimeter) then isn't that a good thing. As soon I write this though, I think this would only apply to kind, responsible dog owners. There will always be cruel freaks who will put an unnecessarily high voltage shock onto a disproportionally small dog. I also now feel there's a difference between a shock collar for use with a perimeter as opposed to a shock collar used for barking. I really do think that's barbaric. Hmm, more to learn about this topic me thinks.