Oh, and a third reason no copyright violation. Perhaps the most obvious. The GPL gives that user the right to use the software and derivatives! (To the limit of the original copyrighted work; it can't give rights to others' expression.) Just because the derivative author is violating the terms of the license doesn't mean that you don't get a license to use that original software. And unless you distribute that software further, you don't need the source code; you can make all the in-memory copies you want.
In fact, that's an exceptionally strong argument for using an Android phone instead of Windows CE or Symbian or other any not Free Software OS. It's more likely than not that those phones are violating someone's copyright, yet you would never receive the benefit of the GPL license and so would be infringing yourself.
So really, anyone concerned with abiding by the letter of Copyright law should be using Android phones.