A friend of mine trains German Shepards. His dogs are extremely well trained. He hates off leash dogs. It drives him crazy a stranger comes along with an unleashed dog and yells don't worry he is friendly. He immediately replies back "well my dog definitely is not friendly". He uses the "not friendly" vests. Still there are those that cross the street wanting to pet his dog.

He does take his dog on walks in crowded areas to work on the dog ignoring distractions. It's amazing how his dog will just watch him for the next command.