Not a conference, but once, I wrote a book. The local bookstore, bless them, staged a meet-the-authors, tech talk. I showed up two hours early, lugging a suitcase with extra books. Cookies and lemonade were laid out, along with pristine pens and pads, chairs in perfect alignment. A very nice, gentle old lady showed up early. I was hopeful. I soon discovered she was retired and occupied her time by going to these library things. We gamely began our prepared talk. Half an hour later another person wandered in. He was probably homeless and was there for the lemonade and cookies. This very kind pair stayed until the end and even asked some questions -- that had nothing to do with the subject, and I doubt they understood a thing I said.