DO NOT PET = DO NOT DISTRACT

A lot of people understand that they're not supposed to pet service dogs because their vests say "DO NOT PET," but often times, what they don't understand is that the reason service dog vest's say "DO NOT PET" is to mean "DO NOT DISTRACT." Saying the dogs name, talking to the dog about how you can't pet them, or smiling at them is distracting them from their job, which is potentially saving someone's life.
For reference about the devastating effects of distracting a service dog, please refer back to this blog post from November. Even if the dog doesn't seem like they are working, they are doing something, which is focusing on their handler and monitoring them for changes or what their handlers needs are. A well-functioning service dog-handler unit should be one where the dog knows the needs of the handler without the handler having to constantly cue the dog, the dog should be prepared and anticipating the needs of the handler in any given situation.