The OP joke kind of reminds me of the music contest, where they had participants play "Night in the Brume." The rules were: learn it by ear and play it, and there will be no sheet music. So I did. After I submitted mine, they said, "Here's the sheet music, everyone!"
I was sitting there thinking, what the f#!^#^. I knew my entry wasn't a winner, but it still felt hokey to me when the rules changed all of a sudden.
It made me wary of every contest to come... So be careful. They might change the rules on you!