Never...he knows what he's talking about. "Bricked" is an over-used and misunderstood term in the iPhone world.
Thank you.
That's really the beauty of DFU mode: it is entirely hardware-based, and cannot be interfered with by any software means. It even bypasses iBoot. You can't even flash the chip that controls DFU mode without taking your phone apart. I promise you, if people can't do a DFU restore, it's because they've got a hardware problem, not because software "bricked" their phone.