[Image description : 4 Panel comic. Panel 1: A Dora the explorer ripoff wearing a fedora and with the fedora logo on her t-shirt is smiling at the viewer. The caption "Fedora the explorer" is over her head. Panel 2: She speaks to a vaguely anthropomorphic chameleon: "Hello Opensuse !" He replies : "Hi Fedora!" Panel 3: OpenSuse Says: "Someone has been using your code while not freely providing theirs despite the GPL licence!" Panel 4: Fedora "Hmmm... Who could it be?" A fox wearing a red hat emerges from a bush in the background. End ]
Microsoft did a similar thing with GPLV2 software. That's one of the new things in the GPLv3, you camnot enforce source code restriction by thirdparty subscription agreements