Really?
You'd think from a purely "Engineering" standpoint it would be much easier just to snoop at Internet Exchanges / Landing stations?
I've always been suspect at the suggestion of physical taps on long distance submarine optics, also not forgetting if you get the tap in without anyone suspecting it how do you transmit the data out ?
a Buoy on the surface with some bonded 4G ? :P
However, I do believe the communication is being monitored, just that saying a cable is tapped has more impact in the mind of the masses.
Biting the hand that feeds IT
