This is how Burning Man did their tickets this year. It didn't work out very well for them but I think it would work well for something like this. You'd get a better distribution of devs and people just looking to get "free" devices.
I didn't get a ticket this year on purpose. 900 is a bit too much for my blood (I pay for it out of pocket and don't want to resell the swag). I went last year and it was both fun and sad. The concert, robots and devices made me go to geek heaven. The sad part was that it felt a lot of folks were there just for the swag. I also went to pycon last year and had an amazing time. The production values were far less but I felt that almost every single person in the room was a craftsman (craftsperson?). In terms of contacts, both events were a bust ... I don't think I socialized properly .. didn't make any lasting contacts in either places. This year, I'm saving my cash ... have already watched a lot of pycon talks on video. Will do the same for I/O
My proposed fix was make people code something simple in JS and then run an automated it before allowing registration. That way, dumb people try to register, and by the time they can Google a solution to FizzBuzz and copy-paste it, all the developers have already registered.