Yeah, I have a feeling that is some publisher Wizards never heard of came to them with a business license setup last month, they might just refuse their inquiry. "Sorry, we're not interested in selling to you".
The "leader" has to be the one to take the big fall if one of the freelancers/allied publishers leaks the content. Anybody who has the money for the kit or takes publishing seriously will not likely attempt this, just because it's too risky. The more people you have, the more likely there will be one bad apple who will decide to spoil it for the whole bunch.
There was another thread here where someone postulates how likely would it be for the rules to be leaked. I have a feeling this setup is designed to prevent that (at least until
4e is actually released).
Additionally, they are only supplying limited qualities of the draft books, so it would be of limited use to the ones who want to pool resources.