Having been to a couple startup weekends, I feel like this behavior would be pretty atypical?
I am aware of how Zaarly was started - Ashton Kutcher was a 'surprise' judge, happened to be a good friend of a co-founder, and subsequent investor. Both founders were Startup Weekend board members. It seemed like a staged event for a company launch.
http://startupweekend.org/2011/03/09/from-zero-to-1mil-in-3-...
Aside from that, have there been others?