No idea. I think there might be a website to sign up or something. My guess is that the majority of people actually chosen work for a company involved, or are friends with someone who is coordinating. But, that doesn't strike me as being very fun job. You go sit in someone's seat while they go to the bathroom and then move on to another one when they return. I bet its sort of stressful too, trying to get in and out of the rows, not get into people's way.