The more nebulous, the fewer contributors. I certainly would prefer to contribute to properly licensed projects; I've had the fun of putting work into a project that for silly license reasons couldn't get into Debian/GSOC/... I'm willing to forgo it in the future.

I haven't done any deck making, so give this low weight, but I imagine a truly collaborative and creative joint project where making up, say, fallacious arguments -> fallacy name notes that are actually challenging is half the fun, and the benefit of copy-pasta is small anyway.