This is true, but there is also some reason to think that surveillance may be somewhat more difficult if outside the immediate operational reach of the US gover

This is true, but there is also some reason to think that surveillance may be somewhat more difficult if outside the immediate operational reach of the US government. So yes they can listen. But if you make it as hard as you can, you make them spend more effort for less. If we could make the internet run more secure encryption generally, then the NSA, forced to target specific end-points, would howl in frustration....