Yes my earlier statement was actually pretty offensive to some really smart hard working and honest dudes, sorry about that.
It still isn't a fair play field, but it's not just stencyls problem, even Ludum Dare suffers from similiar issues.
Even having themes doesn't stop it as themes can often be forced into the narrative or artwork somewhere.
But guess what, the world of games production is not a fair playing field. And most people are there because they want to be. I'm entering the stencyl jam again, with my buddy, we're starting an entirely fresh project for the event, but it's because we were about to start an entirely fresh project, if we were a few weeks in I'd feel it was within the code of honour rules, but I personally would always state the start date of my entry.
The stencyl community is pretty honest and decent, so let's just assume everyone is playing fair, because if they aren't it's tough, and therefore not worth worrying about.