What I meant with respect to balance is the consideration that an independent judicial officer would make between competing rights and competing values that we as a democratic society hold dear to our hearts.
The right to privacy is certainly one interest; the right to bodily integrity; the right to be free from threatening conduct--these should be balanced against the state's legitimate interest in law enforcement. As part of that balance, an independent judicial officer ought to be reviewing the evidence in advance that the police seek to rely upon to justify the illegal conduct they wish to engage in.
It's not a question of the police making the decision themselves, which somehow comes to someone's attention, and stepping back saying, “What I was doing is justified under the Criminal Code.” There are real safeguards in requiring the state to ask in advance for permission and to justify what it is they seek to do, against the harm that may be inflicted upon other values we hold as important in our society.