we aren't talking 24/7 use here dude. Those pieces of metal aren't even at -200C if you consider the fact that the temperature probe wouldn't be reading the exact temperature of the actual transistors. If it was bad, don't you think people wouldn't use it..............This is why it's called 'extreme overclocking' and reaching for world records.
I don't think they are too worried about ruining a CPU or two in the process. The thing would sooner die just from pushing it too far than it would from the cold. AMD even makes their CPUs (yes I realize this video is with an Intel) with thoughts that people will put some extreme temperatures on them, hence why they call it 'fixing the cold bug' so yes these CPU's can handle it just fine, but as I said it's not like it's joe blow 24/7 home use.
These "90nm pieces of metal" aren't being chilled that far and then shaken around, so it's not like they are in danger of being broken like a rubber ball dipped in liquid nitrogen.