It would be a violation of privacy to sit down and read it through. Whether this should be legally actionable (as opposed to just socially) is another question, of course, but nevertheless.

Is the particular violation of privacy you identify actually illegal?

That depends on who's doing it, and under what circumstances. If it's a cop without a warrant, arguably.

My point was just that we respect and enforce limits by means other than technological, and it's correct that we do so.