Do you think people in less affluent neighborhoods have 5 or 6 door locks for decoration, or is it to keep people out, because door locks don't stop people? Do you think those same people have bars on their window because the door locks work? No, because the window is a weak point and dishonest people will not be deterred by 1/8" of glass.
Thank you for dismissing your case. If the techniques described above were not effective, then they wouldn't be employed. They work, because they deter.