Hmm. I friend of mine claimed that requesting trade with another player in World of Warcraft crashed his router. When he needed to trade, he always insisted that the other player should initiate the transaction.

I was tempted to discard this as pure imagination, but this was a smart and knowledgeable fellow who worked as a programmer, so I'm assuming he had done some investigation before he came to this conclusion.

I know too little about networking equipment, but I can see how certain byte sequences (timed right?) would have some magic meaning. Given enough traffic you're likely to end up sending just such a sequence eventually. Perhaps certain versions of the WoW client spat out just such a magic sequence for the particular router he happened to use?