I think you're example is a good example of how weak the arguments for privacy are. All I see are hyperbolic examples. My favorite ones are where people try to bring up how the lack of privacy lead to horrors like NAZI Germany or Iran as if the US is somehow comparable. And they say "But government can change!". Only in la-la land is the US government going to turn into Iran. No developed country in the past 50 years (even ones where privacy is not considered a god given right) has slipped back in totalitarianism.
No, its not. Do you think we are buying any essential safety for freedom? I don't think so. They have a needle in a haystack problem with a large responsibility such knowledge holds.
If you don't think governments can't change, I'd like to hear your opinions on how we went from a authoritarian (kingdoms) to democratic governments in the first place (or vice versa). Everything changes. Even societies change on micro (companies, clubs) to macro (governments or totality of the world) level all the time as new people arrive and old people leave.
US won't turn into Iran over night, it might take decades, centuries even to change into a totalitarian regime. But first sign is trampling your constitution. I'm not saying its going there but it could be going that way.
Why would you need totalitarianism? The government which gave Turing the choice between imprisonment and hormonal treatment using injections for the crime of "indecency" wasn't totalitarian. Developed countries - and the US in particular - violate basic human rights regularly. You don't need to imagine hypothetical scenarios.
That said, I believe this is all irrelevant. Privacy is an end in itself, it doesn't need to be justified.