If they announced what they were going to do then the votes would be probably be more biased towards the favourite theme rather han the favourite entry.
So if everybody likes DA's ideas and not mine, then he'd have a better chance of winning, which as you can imagine wouldn't be fair. (And it my idea is better than DA's, which we all know my idea will be the best, so good that'll blow your socks off...kidding of course, I don't have a clue what I'd pick if I got the most votes)
"Experience never provides its judgments with true or strict universality; but only (through induction) with assumed and comparative universality." - Immanuel Kant