To me it appears quite clear that Broadcom is distributing a GPL'd file,
and thus has to turn over the source code.
Now you may argue this exempts them from this (but it probably still
* Firmware is:
* Derived from proprietary unpublished source code,
* Copyright (C) 2000-2003 Broadcom Corporation.
* Permission is hereby granted for the distribution of this firmware
* data in hexadecimal or equivalent format, provided this copyright
* notice is accompanying it.
But what about in versions distributed for years where that was not
included? That text above is recent addition. To my surprise when I went
to download the driver on their page I found I had an old
~/devel/broadcom directory with a file linux-7.3.5.zip containing files
timestamped from 2004 (the above copyright was added in 2005).
Here, the bcm5700-7.3.5-1.src.rpm file was tagged "GPL".
I'd take that to mean that they didn't understand the GPL when they
originally used it and corrected the situation by removing it. So what
you have is a non-gpl'd binary file with permission to redistribute -
which is far from unique.