In The Dark Knight...Gotham police faced a similar situation to that faced by the FBI in Boston last week, needing to find an unpredictable killer hiding somewhere in the city. Batman pitches in by creating a device that secretly uses every cell phone in the city as a form of sonar, allowing him to constantly surveil everything. Even our superhero considers this device so terrible and potentially destructive to the liberties of the people he’s sworn to protect that he designs it to be used only once—by someone other than him—and then to destroy itself...Bruce Wayne could have saved himself quite a bit of money just by asking people to submit their cell phone photos. Who knew that people would not only not protest, but would...eagerly participate?