There are no immutable constants, gravitational or otherwise, in the world of human ideas. If you want me to agree with you that it's preferable to die than to be noninvasively and incidentally spied upon, it helps that cause not at all simply to say the truth of your perspective on the matter is as ineluctable as gravitation - this rather fails to convince.
We don't win by compromising ourselves and fighting at their level. We win by being true to ourselves and being strong in the face of adversity. The more we can be ourselves, the stronger we'll be.
But what constitutes our desired selves is exactly the discussion. That's the "line" that I was asked to draw and I absolutely drew it for myself and I made that clear. I wasn't arguing that privacy is an immutable construct, I was arguing that law enforcement should view it as such because I feel it's fundamental to our value system. You don't see an aviation engineer arguing that gravity shouldn't exist just to make his job easier. He or she embraces that constraint and adapts as best as possible. Similarly, I'd like law enforcement to just embrace that privacy is an expectation in a free country and work within that reality. Others are free to disagree with me about the true nature of our desired society. For them, privacy may not be an hard and fast requirement. For me it is. That's my line.
Perhaps it creates a necessity. Dying to uphold a principle is fine and good, and very much easier when you get to have the principle and someone else has to do the dying.
Noninvasively spied upon? Having your privacy violated is invasive, by definition. Having a situation where one centre of power has extensive information on the private details of practically the entire population is an extremely dangerous situation, because knowledge is power, and that level of asymmetry in knowledge can (and I would argue will) lead to the population at large being exploited by those within this centre of power.
We, as citizens, need to do our part to keep perspective in the wake of attacks. Yes, they're scary, but they're rare and we should be able to endure them without getting hysterical. But I agree with our founders that we have certain inalienable rights that don't go away just because someone might be a criminal. And while privacy isn't explicitly enshrined in our bill of rights, it's completely within the spirit of that document. Aviation engineers don't try to get the coefficient of gravity changed. It's an immutable constant that's part of the framework in which they do their work. Privacy should, likewise, be an immutable constant that's part of the framework in which law enforcement tries to prevent and solve crime.