Re: if you haven't done anything wrong
-- fruit of the poison tree --
Neatly circumvented by "parallel construction", in which at least U.S. L.E.O.s are well versed, as I assume are other would-be Stasi in nominally democratic states.
Or they could just skip that time-consuming trial thing and send you directly to Gitmo. Or just disappear you if you happen to be a bookseller in H.K. There are a _lot_ of "them" in that "they".