Since the 80s you can spy on anyone's calls using the telco's standard maintenance features. You dial up a number, you then dial another number, and you're basi

Since the 80s you can spy on anyone's calls using the telco's standard maintenance features. You dial up a number, you then dial another number, and you're basically patched in to the second number, can listen in on any current call. There was a different system required by the government for taps, but linemen have their own method so they can diagnose issues. At least that used to be the case through the 2010s. Stupidity and banality is a far greater threat than conspiracy.