The real story here is being missed by everyone:
The iPhone 4 in a Bumper case was dropped TWICE by the sales-weasel, with no damage to the iPhone 4 and only minor scuffing to the Bumper.
Only on the third flipty-flip attempt did the sales-weasel finally break the glass.
So, let me ask my fellow iPhone 4 owners... When you accidentally drop your iPhone 4, are you going to pick it up and keep dropping it until it breaks?
The Bumper did its job. Both of those first two drops probably would have resulted in broken glass without a Bumper.
Next up, the sales-weasel team will shoot a bullet through the iPhone 4 and then complain about the Bumper not protecting it!
Mark
Here's my response to your thoughts:
Here's something you might not be considering.
Perhaps it does take 3 drops on a hard surface to break (kind of like the Wise owl and the Tootsie Roll Pop - 3 Licks to the center!!).
Perhaps the iphone was indeed damaged after the FIRST drop. That small microscopic cracks/spiders dveloped not percevieable to the naked eye. After a few more drops, it does indeed break entirely. There could have been tiny cracks at the edges which ave not yet spidered out until the 4th drop.
My point is this, what if you droped it 3 times in 1 month or 3 months (or whatever) without any noticeable damage, and then on the 4 th isolated drop it breaks.
Could it be a cumulative effect which is taking place? If so, thta would mean that each time the iPhone drops, its glass is compromised slightly. Drop it enough and it can no longer stay intact.
Just something to think about.