They're calling this an eBook Loyalty program, and it is open to everyone. Send in a photo and you'll get a free PDF. While the UPK does sell Epubs on their website this program only gives out PDFs.
Ideally they want you to send a photo of you holding the book you own, but I don't think there's any way for them to verify the identity of the subject of the photo. Nor do I think they care all that much.In fact, their blog shows a number of people whose pictures were taken in a UPK booth at a trade show of some kind: