Ask buyers to provide shipping addresses in case of event cancelation or author pulling out of event etc.

There have been many instances of events being canceled or authors having to pull out of events this year, and even prior to these issues there are always reasons why an author might have to ship preorders directly to the customer rather than them picking it up at the event. Instead of authors chasing down customers for their addresses it would be far easier to include address as part of the initial check out information, and not unusual when compared to most check out processes.