I would suggest, for anybody considering attending a hackathon to not let this totally discourage you.

Not all hackathons are equal. My first was at Launch Fest 2013. It was a great experience and I think the judging was as fair as could be expected. There were a lot of talented people who honestly hacked awesome projects together in such a short time. You can see the 5 finalist starting at 23:30 in http://youtu.be/HPSnsxN4lEs

Also, consider http://openhack.github.io