Who cares, really? I ALWAYS keep my phone in a case. The Apple leather one fits perfectly, looks great, and has saved my phone from ANY damage after about half a dozen drops onto concrete since I got the phone a year ago (and I'm careful with my devices, but s**t happens).
Yeah, carrying the phone "naked" may look and feel nice but the average person WILL break it at some point. It's inevitable. Just get a case and your phone will probably be fine.
err...just logged in after a prolonged absence to let you know:
My phone is an utility. I carry it with me 24/7. As a matter of fact my precious MS/Nokia Lumia 930 was dropped an uncountable amount of times. I don't use a case.
These are accidents. They happen.
I have a completely dented frame. In fact the polycarbonate back doesn't fit perfect anymore and has several breaks on the corner.
My display glass has several really bad scratching marks from keys and sand in my pocket, but never in the entire lifespan of my phone did I experience a broken display.
Now the rhethorical question: Does MS/Nokia use superior glass or is the iPhone design really flawed?
I vote for the latter which is why I still haven't bought an iPhone since the 3GS.