I did actually manage to sign up for this. When the UIP booth first opened (about 9.30) they had 2 clip boards to take down names and e-mail addresses of those interested. The clip boards were put away about 45 minutes to an hour later so I would presume that all the places were filled (there were a lot of people interested).
Even if they put up a sign explaining that all places had been filled it would have been better then what they did.