Comment by seplox

Yeah, but. The side-effect of catching criminals and protecting the children is that they also provide a searchable database of everyone's historical travel habits.

It's my opinion that our historical ideas of expectation of privacy when in public spaces are incompatible with the current state of surveillance technology. Sure, everyone should expect that they might be recognized by an acquaintance when out in public, but I don't think it follows that our entire past history should be available at any time in the future.