Umm, folks... radio signals can be triangulated using direction finding. It's not difficult. You can't have a cell phone without the ability to be located.
ALL cell phones can be located to a good degree of precision, especially in a densely populated area (due to higher density of cell sites).
Also: GPSs are receivers, not transmitters. They receive signals from the satellites to figure out where you're at. Even if your cell phone had GPS functionality (and not just location through direction finding with cell towers), you wouldn't be any more "vulnerable" than with any other cell phone.
And finally: Any three points forms a triangle.
