Looks like no preregistration for past attendees like previous years:

https://plus.google.com/111395306401981598462/posts/Ty3M5UDd...

Ruben Orduz - +Google Developers No pre-registration for past attendees? Also confirmation about no test for registration would be much appreciated.

Google Developers - Just to confirm, registration will be first come, first served on March 27th. We spent a lot of time thinking about this and decided that first come, first served is the fastest and fairest way to give everyone interested a chance to attend.