There have been mentions of the infamous SCO trials. But there, the
situation is different: SCO claims that vast amounts of their code has
been lifted and transplanted in to the Linux kernel. And such claims can
be made by anyone, against any project. This is just lawyers having a
blast and investors gambling.

I feel that this whole discussion is pointless and a real time sink. All
the effort going into this discussion would better be spent by working
on BackupPC and the infrastructure to support it. All I wanted to say is
that CDAs may not be legally possible for all contributors and that it
would require some institution which may have to be tightly controlled
in order to mitigate the risk of loosing the control over the project.