This reminds me of a funny story. Once I pretended to be blind to get a girlfriends Boxer into a restaurant. I put on her sunglasses and did my best Stevie Wonder head-rocking and wrapped his leash short around my hand. He was very well-mannered but hardly a seeing eye dog, and the manager was suspicious but what's he gonna do, accuse me of being able to see? So he let us in.
She pretty much gave us away because she was laughing so much but they never said anything but gave us a very funny look on the way out. I don't think that would work with a Yorkie. But hey, you never know maybe there is a new program underway for seeing eye Yorkies??