Overlook Press comments on an article about how book-signing events go down in New York. It isn’t first come, first serve. From the article:

It’s just that certain branches are simply better for certain types of books. “There are definitely uptown authors and subjects and downtown authors and subjects,” he said. “A lot of it has to do with where a writer has most of his posse. Thus, you’re not going to put the latest Tea Party author at the B&N at 82nd and Broadway,” Mr. Kirschbaum continued, alluding to the store in the heart of the famously liberal Upper West Side.