I get the argument totally, I had a friend who took in non-friendly dogs and she would constantly rant about how many people who approach her muzzled dogs and just start petting them without asking first. In that situation I think people are being morons. On the other hand, I had a neighbour who used to walk her dog off leash and he was a super friendly type and adored me and loved to come over and say hi whenever he saw me out and about, she hated it and would get sour faced when I pet him. In that case, I think if you don't want people petting your dog, keep them on leash and use social cues such as pulling them away when they approach passerby.
