In terms of 'what might happen' it is worth remembering Zimbra and CUPS.
I may be wrong but I think both of these projects require the assignment of copyrights back to
a central entity.
Zimbra, which is a high profile project in a very important segment - i.e. competing with MS
Exchange, nearly became property of Microsoft when they attempted to buy Yahoo.
CUPS (which definitely required code assignment) was purchased by Apple (allegedly to prevent
it moving to GPL3). Apple could close-source the project any time they wanted.
Having seen these two events my feeling is that copyright assignment is to be avoided. If I
was selecting a package for my organisation I would consider copyright assignment to be a