The real lie in those events is the promise to create a team in 48 hours. And I say this from my own experience. Kodesk won the grand prize of the jury of the Startup Weekend Brussels in last January and a week after the event, it was clear to me that I could just not create a business with people I had met a week before. Co-founding a company requires trust, complicity and complementarity. And if you don't have that, your "team" can blow up a good concept with a good visibility.