Why does everyone seem to think this situation would have never happened any other time if only the kid wouldn't have gotten hold of it? People drop things, it's life...I'm sure there are quite a few people on here who have accidentally dropped their phones. It doesn't make someone careless, it's not like we throw them on the ground on purpose. Things happen.
If you think about it though, the fact that this glass "30 times harder than plastic" is breaking so easily is simple science. Take a bat to a glass bottle and a plastic bottle. Which one do you think is going to shatter? Oh yeah, the harder one. There is so much stress put on the atoms of the glass, they have no room for shock absorption such as the old plastic backs did, resulting in a surface much much easier to shatter.
Case and point? S*it happens and people drop things and a guy shouldn't be jumped on because it happened, it's not his fault that the iPhone 4 is such a fragile "strong" product. Don't get me wrong, I will own an iP4 as soon as they come in stock

, but jeesh...it was an accident. If anything this person is helping other users to know this thing is FRAGILE and to treat it very, very carefully. Thank you OP, now when I get mine I will know better.