http://bugs.winehq.org/show_bug.cgi?id=657
--- Comment #65 from Thomas Spear Speeddymon@gmail.com 2010-09-03 23:56:20 CDT --- Publicly available does not mean free to use by anyone for any purpose, however. GPL code can and does get "stolen", by way of someone using code and not posting their modifications to the public; and the "thieves" can and often-times do get prosecuted -successfully- after refusing to release their source.
Same goes for publicly available non-GPL code. If the license forbids it, but someone reads it and then builds or helps build a wine builtin mfc*.dll, and microsoft sees that code in the wine tree, then wine as a whole is in deep trouble.