The chance to be involved in an armed robbery are small in every big city in the world. Based on anecdotes people will always over or under exaggerate the chances.
Just to give a counter example: I lived in Brussels, Philadelphia, Oslo, Sao Paulo... the only place about which I have a first hand "armed robbery" story was in Oslo of all places: a coworker got actually shot in the back when he bravely (but stupidly) turned his back and said "no, you are not going to shoot me".
He was lucky and was only a couple of weeks out but he carried his X-rays of the bullet with him because nobody would believe him otherwise.