I called and spoke to someone in recruiting on behalf of a friend who also got the email. He was flying at the time and wasn't able to schedule a one-on-one before the slots filled. My advice to him and you, after my conversation with recruiting, would be to consider going anyway if his schedule is open; afterall is seems to be a smaller event that costs him nothing (versus dropping $150 for a job fair registration). And in the meantime he could regularly check the weblink given to see if a slot opens up due to a cancellation. There also could be no-shows the day of the event. And lastly if you do get a slot don't be one of the no-shows, unless you want to make a bad impression.