Dont make this mistake. In order for evidence to be admissible in court it needs to be legal (usually). But if information gathering is not going to be subject to scrutiny in Court then everything is fair game. The equivalent of the Stasi are able to do what ever they like because what they do is not subject to public or journalistic scrutiny. The situation in the States where peoples phones are tapped without a warrant would never have come to light if an insider had not blown the whistle. There are no rules because the people who are in government make the rules. Those rules are not made in Parliament. They are not the subject of democratic scrutiny.It is actually subversive conduct condoned by the subversives.