Many travel "hacks" are relatively harmless. Hidden city ticketing might just be the riskiest among them. Although this strategy can help you book cheaper flights, it exploits airline pricing gaps and carries risks and consequences that could leave you stranded or penalized for future flights. We'll take you through the pros and cons so you can make a well-informed booking decision.

What are hidden city plane tickets?

Hidden city plane tickets are a pricing loophole that exists due to supply and demand and the effects these factors have on airfare for different routes. This strategy, originally proposed by the founder of the website Skiplagged, involves booking an itinerary with a layover at your intended destination and intentionally exiting the airport after your first flight. Why do it? Sometimes this method is cheaper than booking a direct flight to your desired destination.

Here's an example: Say a direct flight from Washington, DC to Denver costs $430. You see that adding a layover in Chicago brings the ticket price down to $233. Meanwhile, a direct flight from Washington, DC to Chicago runs $320. Hidden city ticketing in this case would mean booking the flight from Washington, DC to Denver with a connection in Chicago, and just leaving the airport during the layover in Chicago. With this hack, you'd save $87.

While that's a savings of ~25.5%, taking advantage of hidden city flights has several drawbacks for both airlines and travelers that you may want to keep in mind. Here are five to keep in mind.

5 things to know about hidden city airline tickets

1. There's no checking luggage

Checked baggage is routed directly to the final ticketed destination. So to take advantage of hidden city ticketing, you'd need to pack a carry-on — ideally one that can fit under the seat in front of you.

Taking an additional bag for the overhead bin has risks. Imagine you get to the gate and are told that the flight is full and the airline is now checking larger carry-ons. There are two possibilities with gate-checking your bag. One is that you'll be able to pick it up on the tarmac or jet bridge when the plane lands, but it's also possible that airline staff will tell you it'll be checked through to your final destination. Is that a risk you want to take?

2. It's an inconvenience for other travelers

After being on the flight for the first leg of your trip, the staff for the next flight will expect you to board. When you don't, they'll make a final call for you in the terminal. And another. And another. They may even delay the flight while waiting for you to arrive at the gate. This is even more likely if you're traveling with other people who are also doing the same hidden city strategy.

While you've saved some money, this is a big inconvenience for the airline and the passengers of that flight.

3. There could be unexpected reroutes

It's not uncommon for flight plans to change due to a variety of factors. If the airline changes the schedule, the layover can change too. Or the flight could be rerouted due to inclement weather and you could end up flying to a different layover city or rebooked direct to your final destination instead of your intended layover destination.

4. Never use it for a round-trip itinerary

If you skip any leg of your journey, the airline will consider you a "no show" and cancel the remainder of your itinerary. So if you need to fly round-trip and want to book hidden city flights, you have to book two separate one-way tickets. For example, if you book Washington, DC to Chicago to Denver and miss the Chicago to Denver leg, every remaining flight on your booking, including your return flight home, will be canceled.

5. Biggest risks of booking hidden city tickets

Intentionally booking hidden city plane tickets violates airlines' "contracts of carriage." It prevents them from selling that empty seat on the second flight. To penalize offenders, airlines may revoke frequent flyer miles or even issue a temporary travel ban. Because of this, experienced travelers often avoid attaching their frequent flyer number to these bookings to avoid being tracked.

Final thoughts: Hidden city flights

While hidden city ticketing can unlock savings for savvy travelers, it requires careful planning and a willingness to accept considerable risks. Before you decide to skip that final leg, weigh these potential downsides against your budget to ensure you don’t end up paying a higher price in the long run.