"I just have to say that if it turns out that you are using open-source and licensed code on a project that you have closed off, you had damn well better be prepared to take some major heat. If it's one thing you don't do to the OSS community it would be to test the waters of legitimacy or legality of those licenses."
As long as Canonical does not redistribute their program, they can mix closed and opensource as much as they want. Thats what the GPL sais. Many servers of Google are running on a modified Apache, but as long as Google keeps the source in-house, there are no licence violations.