Communication Ethics book part for Wire Tap. (This is an automatically generated summary to avoid having huge posts on this page. Click through to read this post.)

A wire tap occurs for some connection when a wire tapper interferes with the medium in such a way that it sends a copy of the message to the wire tapper. A wire tap is usually targeted at a particular entity, which may be either the sender or the receiver of this particular connection, and the wire tap is without the consent of that entity. (If the entity did consent to this arrangement, we would model that as the entity opening new connections to the wiretapper and deliberately sending new messages, containing copies of the original message, which is an entirely different situation ethically.)

In accordance with the only humans communicate property, it is not a wiretap if no wire tapper ever sees the message. In theory, when one sends a message over the Internet or a phone call over the switched circuit network, there are any number of copies made of the message en route to the receiver. As long as the message is not stored and nobody ever sees it, that's not a wiretap, it's just normal operation.

This does not cover all forms of surveillance, of course, just communication interception.