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.
One anecdote that might be telling: someone left their wallet in front of me in Stockholm metro. I was concerned, trying to imagine a way to get it back to him; the Swede sitting opposite me was surprised that I didn’t know I could hand it to any employee of SL safely.
Sure, there are isolated anecdotes like the ones you quote - but there is not a single area of either Geneva or Nyon where I wouldn't walk around with an iPhone at night (I grew up in the Nyon region, then moved to Geneva's as a teenager FWIW). The worst that you can expect is someone trying to sell you drugs, or begging, or getting into a drunken argument (like basically anywhere in the world where humans live)
Not to mention, that's probably the "worst" region of the country - I live in Bern now and you'd be hard pressed to find someone who would not bring your iPhone back to you should you leave it on the sidewalk at night.