My Friend the Test Pilot

I met my friend the test pilot, who had just received a lot of publicity for a record round-the-world flight by hot-air balloon. With my friend was a little girl of about two. "“What’s her name?"” I asked my friend, whom I hadn’t seen in 5 or 6 years and had gotten married four years ago. "“Same as her mother,"” was the reply. "“Hello, Susan",” I said to the little girl. How did I know if I had never seen the wedding announcement?