This guy clearly isn't lying, I've seen at least 2 other people with the same thing, one of which has a multiple page thread on the same topic. You can't bend a phone like that without breaking the screen. This is a manufacturing defect and it's unfortunate that Apple won't recognize that.
I don't think they are lying either, but I have to point out that Gorilla Glass bends quite a bit. If you've ever seen any of the promo videos, it's pretty extreme how much it can bend without breaking. Sitting on it COULD bend it without breaking the glass if you did it right. But I'm not going to assume that's what happened to the OP.
Edit: Old video, but gets the point across...
http://www.youtube.com/watch?v=Ope6uViLcEY
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I work for a huge international company. After a meeting on Friday, we decided to track the employee experiences with iPhone 5, just for fun.
So far we have a massive number listed, yet not one that is bent. I find a condition like that very interesting. It will be fascinating to learn what caused it.
I work for a huge international company as well. Are these company issued phones? I can't imagine that many people having iPhone 5s already. I haven't seen anyone else in my company with one yet (although if I pull out our EAS logs I'm sure I'll find some).
Edit: Realized I had a report sent to me yesterday. Seeing 75 iPhone 5s connected to our mail servers so far. Not too bad. I was really surprised at how many people had already upgraded to iOS 6.
Funny thing, my far smaller Church, there were at least 4 of us on Sunday with one.