I think the question is the other way around, what happens if you
use GPL/ed footprints/components in an commerical design, Will
somebody come along and say that you'll have to give the
schematics/pcb files to the public becuase you used GPL'ed
Symbols/Footprints to produce the board.
Well, they *can*. So far, it's been a question of *will* they.
Maybe it would be possible to get the footprints/symbols under a
license similar to the one of the libc, which allows you to use it
in commercial projects without having to release the source of your
project.
Bad example. Linux's libc is GPL'd also.