While I get your point, most traditional landline networks do encryption at the premises. Look at, for example, the Secure Terminal Equipment ISDN phone used by

While I get your point, most traditional landline networks do encryption at the premises. Look at, for example, the Secure Terminal Equipment ISDN phone used by defense agencies. To state the obvious, the alternative of provider enabled encryption would be a bad option anyway; the track record of most telcos doesn't inspire a lot of faith in their ability to keep anything a secret. It wouldn't be hard, and certainly not a capacity strain, to get some old modems and haul encrypted PCM in realtime across them. Or even to roll your own PSK/FSK standard to transport said PCM over. There's no packet format or anything you're necessarily limited to. As for cell phones themselves, I can certainly see the threat. Even without going into Batman-esque theories of someone putting malicious software on your phone that activates the mic when it's idle, it's well known that the cellular networks make extensive use of GPS capabilities. With access to an operator's network, it would probably be relatively trivial to build a very detailed history of someone's whereabouts.