Looks like the winning team hacked the hackathon by finding a solution to the problem of "how to win a hackathon" in a clever way. I say well played. If the judges accepted this PDF entry, and it was within the rules, then it's very bad sportsmanship for the other contestants to say they didn't deserve a prize. The fact they didn't write any code makes absolutely no difference at all. Hackathons are about finding solutions to problems, not writing code.
It doesn't look like they found or exploited any solution but rather the judges were determined to let them win regardless of the quality of their entry.
