Major problem with the business plan competitions I've been to is the IP. One Conversation went:
presenter: its a great idea.
judge: so what is it.
presenter: i can't really say, just trust me.
On the flip side, when a friend of mine won a competition he then couldn't patent it, as he had declared it in a room full of people.
As a result, most of the more open competitions tend to focus on quirky ideas, that could not be patented anyhow. I often find they are little more than pr exercises to lift the profile of the entrepreneurs society and/or business school, not bad in itself, i guess, but I always get more of an institutional feel about them.