iPhone 4 overheating: is your Apple handset toasty?

Back in the aftermath of the iPad launch, various users taking their new tablets out into the wild found the Apple slate could be quite cautious about overheating in the sun.  Now we're wondering if the same thing could be happening with the iPhone 4; HardMac found their iPhone 4's thermal protection – which basically locks you out of the phone until it decides it has cooled sufficiently – kicked in when the handset was in an otherwise cool room.

Apple's own technical guidelines suggest iPhone 4 users are good up to around 35-degrees centigrade; HardMac say the room their handset was in was only at 25-degrees.  The phone wasn't being charged and hadn't been actively used for at least an hour.  Cold to the touch, it nonetheless required a full reboot in order to become functional again.

Now, this could be an isolated incident and nothing more, but we're also wondering about cooling for that speedy 1GHz Apple A4 processor (the same chip in the iPhone 4 as it is in the iPad).  Anyone else seen overheating errors on their new iPhone 4?