I have no problem with folks using whatever they want , as long as it doesn't harm the dog , mentally as well as physically ……… I just prefer to use harnesses , and really long lightweight leads . I got 3 unattended dog hanging or choking itself to death on their collar stories ……… I have very "discerning" respect for folks that "protection" train their dogs , and the "trainers" teaching these folks and training their dogs ………… my dogs can and do go anywhere , can everybody pet them ? not all of them , but that makes no difference , their not trying to bite anyone , the ones don't like strangers just ignore them …… they are all strange dog aggressive , everyone i've ever had , some been over the top , they view small animals as food , they view large animals as something to catch ……….. I can ride a bike at 15-20 miles an hour with a dog leading , tied to handle bars on a 20ft lead down a narrow horse trail with wildlife popping out all over the place, running across the trail right in front of a dog that likes to eat them , without the dog ever pulling or losing sight of what were doing …….. 98% of them I have raised from birth , but I have gotten a few adults , and some of them came with problems ………….. folks looking for dogs to make into protection/guard dogs , imo , are the ones going to cause the problems for other dog owners ……… in the US we can have guns , much safer for me and my dogs …...