Can Mandrake really do this? http://www.mandrakesoft.com/products/mnf/license
Sure. And I even tend to appeciate it.
they say that owners of the commercial license are not bound by the GNU/GPL anymore. They can change the sources and are not forced to make the sources available.
This only applies to the code they wrote themselves:
Q. Most components in your Software are covered by a Free Software license. How can you create a dual-license?
Only the components created by MandrakeSoft are under dual-license. All other components retain their own license and terms.
/alessandro