So, it didn't occur to the organizers to keep a copy of the pre-reg info on a flash drive? Or even dead trees? Maybe it's different at a fandom convention, but when my employer is called upon to organize a "professional" conference (one that issues "contact hours"/continuing education credits good towards maintaining a professional social work license for example), we have a back-up or two on flash drive and a set on dead trees in case something goes wrong with the laptop. Actually, we tend to use the dead tree version more, several copies actually. This way, we can have multiple check-in stations for the folks who preregistered. Laptop and printer are usually designated to the walk-in station.