I believe that idea of crowd sourcing in crime investigations, as well as more general discussion on surveillance vs. privacy and even more general topic of security vs. freedom, can be brought down to the issue of trust citizens have in government. Specifically, I don't think that surveillance and data gathering is the problem per se, but that use of information gathered. If all government institutions to comply to the strict provisions of constitution and to rule of law, and use gathered information strictly within constitutional framework, citizens shouldn't have much to worry about. So the real question is - do we believe that our governments will, without exception, behave in such a way.