In the 80s when I zipped around the world a lot more than I do now, I knew all the bucket shops to get good international fares from, I would buy tickets which originated and ended in London, because that worked out 20-40% cheaper than buying tickets in the US. At any given time, my briefcase would have multiple tickets. A big risk, since all tickets were paper-based back then. But a risk worth taking given the travel arbitrage opportunity.
I happened to read in Frommer's BudgetTravel that you can play those arbitrage games with on-line reservations now. As the article describes though, some eager beaver airline or car rental employee could ruin your trip. As the Hertz rep says "It appears that a customer could get a better rate by pretending to be from a different country, but there's no guarantee that at the time of rental, that rate would be honored"
On the Internet, nobody knows you are a dog. But man do they get all huffy when they find you are a German Shepherd not a Siberian Husky :)
Update: Jeff Nolan points to another form of arbitrage - and for airlines to lose more money. For years now, Southwest has hedged its fuel economics. So during the recent oil price run up, United did too. Except it did at over $ 111 a barrel and now prices are down considerably!
