There's a very simple "rule" that if followed would solve most of these problems ... that is that no dog i ever allowed to approach anyone unless it is invited to do so. Dogs can be aggressive, they can bite, they all certainly have muddy paws and slobbery tongues and there is no reason why non-dog people should have to put up with this unless they wish to. You wouldn't (I hope) let your kids kick a passer-by on the shins or smear chocolate covered fingers on their coats - so why let your dog do this? I am tired of being growled at or barked at or worse on walks in local parks.