Airline passengers have long had a trick up their sleeve to save money and airlines work like crazy to fight it. It’s called throwaway ticketing.

Booking DC to Chicago might be expensive, but flying DC to Milwaukee via Chicago may be much cheaper. So you book the ticket to Milwaukee, get off the plane in Chicago, and don’t take the connecting flight.

• This is generally against airline rules. You may think you’re buying a ticket to fly DC to Chicago and Chicago to Milwaukee, and it should be up to you to decide what you do with each (and the New York Times “Ethicist” says this is fine and the late Justice Scalia did it himself) but the airlines look at it as you buying a DC- Milwaukee ticket, a totally different product, and using it to get something more expensive (DC – Chicago).

• If you do it frequently an airline may ban you, or may close your frequent flyer account. It’s a good idea not to credit miles to the program of the airline you’re flying. United has threatened to send customers who do this to collections and Lufthansa has sued (and lost).

• This doesn’t work with checked luggage (that will go to the final destination on your ticket) and it doesn’t work if you have to gate check bags, so be sure to board early enough that there’s still overhead space. And if your flight is cancelled the airline may want to re-route you to get you where they think you’re going.

• You can usually only skip the last flight on your itinerary. Skip anything else and the rest of your itinerary will usually be cancelled. That’s why this works better with one way tickets.

God Save the Points points out a loophole that makes skipping segments on a ticket perfectly legitimate. And you can even do it on your outbound flights, rather than only skipping the last leg of a trip.

Italy’s competition authority found that it wasn’t clear to consumers that skipping a flight on your itinerary would cancel all the rest of their journey. British Airways and Etihad were fined, and agreed to make it clearer to customers.

Some airlines took compliance with the decision more seriously. Emirates has the most generous policy for tickets issued in Italy:

• If you do “not shown up for a flight for any reason” you can keep the rest of your ticket.

• This applies “to passengers holding tickets issued in Italy, no matter their point of origin.” (Emphasis mine)

• There’s an email address and a phone number to use to ensure your itinerary remains intact. You just have to let them know within 24 hours of (each of) the missed flight segment(s0, and at least two hours prior to the next flight (that you’re going to take).

Lufthansa lets you use your return ticket even if you did not fly the outbound as long as the ticket was issued in Italy. It’s not clear if their policy would allow you to skip the first segment of your outbound and keep the rest, however.

So how do you get your tickets issued in Italy? You don’t need to find an Italian travel agent, there’s one on the internet. The simplest way is to book travel at Expedia.it.

How can this save you money? Let’s take Emirates as an example. They will sell travel less expensively from certain cities than if you start off in Dubai. Search any origin city that you can buy a ticket for issued in Italy for an itinerary connecting through Dubai, call Emirates and let them know you didn’t take that first flight, and start your journey in Dubai.

Many airlines don’t have this rule (such as British Airways and Etihad). And those that do may not be super familiar with it. However it’s a published loophole, based on a court ruling. Most Americans won’t use this often but it’s something to keep in mind.

More interesting is that it points to how other countries see airline rules differently, as anti-consumer, than how the US does where there’s little consumer recourse against a carrier for anything other than violating its own published rules. (That’s because the Airline Deregulation Act preempts lawsuits based on state contract claims of good faith or fair dealing, and sends customers to the Department of Transportation as their avenue of redress.)