Do they actually encourage innovation / entrepreneurship? What's valuable about them? What do they do right? What do they do wrong?
I agree with you Evan, this is about stepping outside your comfort zone and networking.
However, let's pretend (and this is NOT a hypothetical by the way, but I don't want to call anyone out by name) someone goes into a startup weekend believing they will actually start a company that weekend. They may have an idea, they may not.
Then, they come out of the weekend energized. They're going to do this! But they're not a developer, so they get some developers "on board". They start trying to raise money because "once they raise money, the developers will 'build it'"
So now we've got someone who believes startups have software that is just "built" and then they have the software