Re:Yes, it is done at the telco (Score 1)

Perfect recordings every time, zero call quality issues.

Exactly! I always laugh when a TV show or movie shows a security person entering the room with a black box and waving it around the walls and phones to verify it is a "secure" location. Duplicating data at the switch is undetectable (unless you have a snitch at the telco). Or the other laughable TV or movie moment is when a black van is parked outside a location with a reel to reel tape recording conversations. Who uses analog to record such stuff? Let alone reel to reel tapes. Most eavesdropping is done remotely and digitally.