I disagree, warnings have been given where appropriate, and as is clearly indicated all overclocking is at your own risk.
I have had problems overclocking with a dual monitors for some reason as it keeps resetting......and says that it is no longer over clocked, but the guide is clear and displays step by step, specially if you also look at the other link to the guide........
How did he get "lucky"? You can't sue him for anything. It even says on the title page, "Overclock at your own risk!" So, you overclcoked, at a risk. Your risk ran up and you fried a 7800GTX. In my opinion, I don't think they should refund you a new card, you fried it, you pay the price...