Do you have references to court cases where there's been a GPL infringement (by including GPL code in a closed source project) where the infringing product was simply forced to pay monetary damages and wasn't also required to also publish their source code? All of the GPL infringement cases I've heard about have ended up with the infringing party being forced to release their modifications to the code.
I know of several IP lawyers who believe that simply using GPL'ed headers in a project can cause the entire project to be covered by the GPL. The root issue lies in the language of section 2b of the GPL: "You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this License." What constitutes a "derivative work"? How much code do you need to include for it to be derivative? Is it 500 lines of code? 50 lines of code? 1 line of code? I don't know and neither do you.
The next paragraph of the GPL attempts to clarify section 2b: "These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it."
So what constitutes an independant and separate work? For instance if the application depends on functionality embodied in the headers and cannot be implemented on Android *without* the headers, it's possible that it could be considered to be a dependant work and thus not an independent and separate work. Neither your or I can tell the answer to that, that's up to the courts to decide.
In copyright infringement cases, the only thing that matters is actual case law, and there have been very few cases involving GPL infringement that have actually been ajudicated in a court of law.
And because there is very little case law involving the GPL (at least in the US, I know there's at least one German court), it's not clear what constitutes "infringement". And until that is adjudicated in a court of law, it's just a matter of what lawyers think. There's plenty of FUD on both sides.