The thing about service dogs is you are not supposed to approach, pet, touch, feed, command or talk to said dog. If you have an allergy to dogs, common sense dictates you would do none of those things in order to keep youself from an allergic reaction or stay alive. That dog is trained to not let a blind person walk into traffic and many other purposes. You can see the dog to avoid, a blind person can't exactly see the danger that approaches them.
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