[aruanan]

At any given time there must be more people out in the population than are available to listen to all those people.

That's what computers are made for. They can monitor zillions of phone calls and conversations electronically, flagging the invaders of privacy when certain words, combinations of words, or frequency of certain words are detected.

[stuartcr]

Don't you have to buy one of these first, or do they come free with the vehicle?