While packaging 0.7, I opened COPYING file. Something suprised me: there are non-free data licenses among them:
http://creativecommons.org/licenses/sampling+/1.0/
http://www.soundsnap.com/licence
(I'm checking Free Art License at this moment, since I'm not sure about that one)
If not possible to avoid such licenses, would it be possible to at least package such data as add-ons, not in the main package? What do you think?