So, what happens if one license 0 project (A) wants to depend on another license 0 project (B)? The way I can see it, there's three possibilities:
* project A is now commercial and has to pay project B for the license
* a commercial project that wants to use project A now has to track down and pay both the owners of A and B (and any other license zero dependencies)
* a commercial project that wants to use A pays for A and B gets nothing for it because they are being used by project A (not commercial) and only incidentally by the commercial project.
* project A is now commercial and has to pay project B for the license
* a commercial project that wants to use project A now has to track down and pay both the owners of A and B (and any other license zero dependencies)
* a commercial project that wants to use A pays for A and B gets nothing for it because they are being used by project A (not commercial) and only incidentally by the commercial project.