Just talked to a guy at the Sarasota B&N. He said up to 48 hours because they have to physically go through the emails. And like you stated, he told me that if they post on Facebook that they have completed the task, and you didn't get an email, then you didn't get a ticket. They will not notify you that you didn't get one.
Not sure if it's correct or not, but he said there were a little over 1,000 emails sent. I'm guessing there were more than that, but you never know.