Sure, events tickets are used for a number of purposes for bigger authors. 1) We only get more authors if we have good signings. The evaluation is based on a number of things: media, attendance, but most of all front list sales, i.e. the new book. These are in-store sales, not from other places in town. It's unfair, but that's one of the ways we get judged. It helps that we are a reporting store to the New York Times and Bookscan to help get Turncoat on the bestseller's list for the next week. One of the big reasons an author tours the first two weeks of a release is to get on the bestsellers list. 2) This also helps us take care of our regular customers first. We like to bring in authors to make our store a great place to meet people and to hang out. Most early line numbers are grabbed by our local customers. 3) This allows us to set up the lines in order of when people bought the book instead of how soon people arrive. This helps people coming in from work or other situations where they can not wait around for a long time. ie kids, husband, wives, and other people who might not understand why you should leave work early to go see some author that they have never heard of.
But for your question. Everyone can still get their book signed. Without an event ticket you can wait until the last person with an event ticket. We are happy to let people who purchased the book elsewhere to get their book signed, and meet a great author. We just want to take care of our customers first. I understand if you can't wait and are going to get the book early. I would say that we can still take orders over the phone, and each event ticket can get three items signed, and I know for a fact signed Jim Butcher books make a great gift.
Brian