The government does not welcome free thinkers.  They have taken away simple things like porches so people cannot just sit around and think about their own thoughts.  Being a pedestrian is rare because walking creates thinking time; it is frowned upon.  When Montage meets Clarisse he realizes that she is slightly different than most of the people he knows.  Yet he finds her incredibly interesting.  For one thing, she takes walks at night and just lets her thoughts wander.  Cars in the future are made to go much faster.  Thus forcing drivers to concentrate more on the act of driving and the dangers, rather than their own random thoughts.  People are taught to memorize facts and figures and not have their own opinions, especially if they are different than the ones of the government.  The man who the public believes was Montage was probably killed because he was merely out for a midnight stroll in the wrong place at the wrong time.  That walk costed him his life.  He was a victim of free thinking.