Oh, I didn't realize they had a binary-only distribution that was _different_ from the source distribution.
DIFFERENT is not relevant. I could today ship a binary verion of
postgresql in its present form as a proprietary product with no source
code. No license problems arise from doing so. Allowing GPL code
into the base system causes the problem.
As just said, this is a good thing from the point of view of
encouraging participation and commercial success. As long as the open
source version of postgresql remains a well-designed, solid product it
behooves any commercial distributor to aid in its maintenance rather
than take on the whole thing. Ideally, they will contribute any fixes
they make so that all can benefit and perhaps more importantly so they
don't have to maintain the separate fixes any longer.
Cheers,
Brook