I like the 'Working Dog, do not pet'. I think it would make someone think twice. I think some folks think that a service training dog means the trainer is taking it out to socialize it so petting is welcomed. 'Working Dog' looks more serious. At least to me.
Last weekend, I saw two different dogs at two different places that had 'service dog' vests on . Both CLEARLY were not in training service dogs. One at Walmart that the handler kept grabbing the dog by the shoulder and hind quarter skin and throwing it on the ground yelling 'DOWN!' which is why I even noticed them.
Second dog was a Cocker mix that was pulling and dragging a young girl all over the store. While her boyfriend followed laughing. It made me SO ANGRY!!!!
Hondo Von Dopplet L Bauernhof "Hondo"- GSD
Lilie's Tug McGraw "Tug" - Golden Retriever
Maggie - Mini Dachshund (Rescue)
Lonestar - Texas Blue Lacy
Funyon, Ashe, Soot - Barn Cats
Scooter /1/2 Arabian, Shadow, Katie / APHA