Right to silence, right to thoughts, and ethical application?

I was really struck in class over the idea of one's right to another's inner thoughts. The constrast between a right to knowledge and a right to silence particularly caught me - at one point does one's privacy begin to supercede on what could be accomplished should they speak up? I almost felt myself turn to this side before the comparison to wire tapping complicated matters further. On the one hand, the practice is done with the intent of criminal investigation. On the other, it constitutes a MASSIVE invasion of privacy, bearing so much personal information that could be wholly irrelevant and yet must still be sifted through (I keep thinking of The Lives of Others, a film about an East German home bugged by the Stasi and one man's struggles with the responsibility because he grows so attached to his target). When put in a crime context, I feel as though those pertinent have a right to speak regarding any part they may have taken in this crime, but we also have safeguards in place (for example, Miranda rights) to allow these people to protect themselves, as well as to avoid further incriminating those tried for the wrong crime. Put in this context, I do feel like while there is an obligation to speak out against injustice, there is an ever present right to silence, lest we fall into a French style of guilty until proven innocent that forces one to speak.