Overclocking isn't a risk at all. If you want to overclock your hardware, you look for references for other from other people who have overclocked it. This is why some manufacturers have their hardware OC ready and OCing saves you a lot of money.
An i5 2500k you can OC it to stock 2600k with absolutely no harm to it, of course the i5 won't have hyperthreading, but it's still at 3.8-4 GHZ saving you two hundred bucks.
I'm also not trying to deny that overclocking will ware down your hardware faster, but I've clocked my GTX 570 2.5 VRAM to 860MHz and have had no heating problems or any sign of it dying soon for the past 2.5 years.
It can be a risk, fi you don't know what you are doing. What works in a specific configuration may not work in another similar one. His cooling specs may be better. His memory may be better for OCing, PSU, etc. If you OC your system you run with all the risks, even if they never trigger: with an already OCed card he doesn't run the risk, doesn't void the warranty and doesn't have to go into the process of finding the sweet spot for OC. He has the money to spend, and he doesn't seem to mind spending that extra for it. If he's up to it, why not?
There's one last thing: All systems degrade form use. OC'ing degrades them faster, depending on how much you push it, this is a fact all computer systems obey. Some OCing is gentle enough to degrade them very little, so it is insignificant, but some people can push them a lot. Some configurations, especially with bad voltages, little testing and bad cooling, can break the system. If you are careful and use common sense, that probably won't happen, but its up to the individual user's risk to find out.
For those interested:
http://www.tomshardware.com/reviews/overclocking-guide-part-1,1379-2.html