Given a game where:
- Source code is licensed under a free (libre) open source license, e.g. GPL, MIT, etc.
- Assets such as images and music are licensed under Creative Commons Non-Commercial.
Is it correct that making the assets available non-commercially only prevents other parties from distributing the whole package (i.e. executable w/ assets) for a price, but those other parties could still undercut the creators' attempts to sell it traditionally (e.g. distributing it for a price) by distributing it for free, since they could legally obtain everything needed to rebuild the game?
Would dropping just the assets' CC license and instead retaining full rights for them under Copyright make it illegal for other parties to distribute the full package? This would be assuming no one had obtained a copy of the assets while they were under the CC license.
This question was inspired by the "required proprietary parts" section of this Wikipedia article on OSS business models. It describes this exact scenario for the Steel Storm game, however for the reasons above I wouldn't expect this example to actually be viable.