If you enjoy the talk you can purchase books at the book sellers tent way back at the entrance. The authors go there to sign for about fifteen minutes after their talk. This means you can't get your book autographed and also watch the next author's talk. I did get two of Ruth Ohi's Chicken, Pig, Cow books signed (to William and Jadzia, so I can pretend they are for them).
So here's what I propose. There should be at least a fifteen minute buffer zone between talks. In addition to the main bookseller's tent, there should be a small selling table set up at each venue that features books by the authors presenting at that location, so you can buy and get your book autographed right then and there. Then you can have a little time to travel between venues, or get kettle corn, or pet chickens, or whatever. Simple right? I'm going to write them a letter suggesting it.
My other suggestion: trays for the food sellers. Children cannot carry their own grilled cheese without dropping it.