But can I add that like Falconius says - I agree that I dont think non CC work should filter into the CWBP so as to make only part of it shareable. If you make your own stuff then share it to the CWBP as CC you can still sell it yourself as well but don't claim that bits you add to the CWBP are not CC licensed.
We had Gamerprinter who you may know well being a popular poster made a set of oriental styled maps called Kaiden which he wanted to be on an island off to the West of Ansium. I thought this was fine but he should not use the island thats there as part of the main map as a Kaiden map template. We just said to people dont map in that bit and assume that you can run Kaiden adventures there. But we didn't have modules of Kaiden appearing as part of the CWBP. I am not sure what became of it but it was useful to split that out and away from the CWBP else there would be problems.
You just cant end up with a situation where everybody pools into the project and one person monetizes it for himself so CC guarantees that it remains free and shareable for everyone.