Driver's license?

While  in a store yesterday paying for a purchase, the gentleman behind the counter asked for my driver's license as ID.  This happens quite a lot.  It happened more when I didn't have a guide dog with me.  Tulia was right there by my legs so I said, "Do you imagine I have a driver's license?" as I pulled out other ID.  "Why wouldn't you?" he said and then Tulia moved and he said, "What is that there beside  you?"  He sounded a bit scared.  "My guide dog," I said. "Oh oh I'm sorry.  I didn't notice.  Oh what a cute dog!"  I had thought he might be dog phobic but he just hadn't seen how I entered the store I guess.  Tulia is better than a driver's license any time!