I trust the guy at Droid Life. Wasn't some random dude, it was the main guy at the site. And it's freaked me out enough that when I'm at my parent's house, I'm not putting my bare phone on their granite countertop.
However, I do think it had to have been more than a gently placing the phone on the stone countertop. It HAD to be.
Yes, because site admins are always right about everything all the time. This whole heat shock stuff is nonsense. The phone doesn't get that hot, and room-temperature isn't that cold. At worst, Kellex had a defective phone. The glass either had a manufacturing problem or it was seated improperly. More likely, he broke it, since he also broke an Optimus G, which has been out longer than the Nexus 4 and hasn't had a big issue with this.
Look at THIS THREAD
, if the glass has enough flex to creak, then it's got enough flex to handle any heat stress that doesn't involve you sticking your phone in boiling water after keeping the phone in your fridge.
As for some LG guy claiming the back isn't glass, I'm skeptical of that too. It might not be a proprietary Corning formula, but it's not plastic either, which means it's almost certainly SOME kind of glass.