英語版の管理サイトのライセンスチームのディスカッションから、この問題に関連する重要な場所を二つピックアップします。
http://05command.wikidot.com/forum/t-2171743/russian-youtube-audio-versions
http://05command.wikidot.com/forum/t-2171743/russian-youtube-audio-versions#post-2838040
The most important thing to remember here is that the SCP Foundation is itself CC-BY-SA. The "Foundation" as an expressed and written entity began here (you can find that discussion here: http://www.scp-wiki.net/forum/t-76752/foundation-or-organisation ) under the CC-BY-SA license. Anything featuring anything that originated on this site (The SCP Foundation, The Serpent's Hand, The Global Occult Coalition, ect) can not have an additional element added to the license under which it is released.
If you post works to your site featuring content involving anything that was first written on the main site the author does not have an option to release it under an NC license. A generic story involving the paranormal would have that option, but that's likely not a majority of the works on your site.
http://05command.wikidot.com/forum/t-2171743/russian-youtube-audio-versions#post-2838171
To elaborate:
This corresponds to WIPO Copyright Treaty, article 2 which states "Copyright protection extends to expressions and not to ideas, procedures, methods of operation or mathematical concepts as such". In particular, this means that "themed on" works are independent copyright objects that can be used by agreement with their authors, as per Berne convention, article 2(6).
The SCP Foundation specifically is not just an idea, though.
"Shadowy government organization that locks up paranormal artifacts" is the idea behind the SCP Foundation, and that idea cannot be copyrighted. (See: Raiders of the Lost Ark, Warehouse 13, everything that originally inspired this fiction.) The SCP Foundation can and is copyrighted, as well as licensed, etc.
That's why authors can't make their own SCPs or Foundation Tales under an NC license.
要約しますね:
SCP財団はただのアイディアではありません。"Shadowy government organization that locks up paranormal artifacts"ならばSCP財団の根元のアイディアですね。このアイディアならば著作物ではありません。 そして、SCP財団そのものがCC-BY-SAライセンスです。このため、自身のSCPや財団TaleにNCライセンスをつけることができないのです。
