This sounds interesting?
Just don't book a round trip, don't check a bag, don't do it too often. Also you're gambling that they don't cancel your flight and book you on a new one to the city you don't actually want to go to (that no longer connects via the hidden city). You can get half price tickets sometimes with this trick.
https://www.bitsaboutmoney.com/archive/seeing-like-a-bank/
> As a sophisticated user of the banking system, a useful skill to have is understanding whether the ultimate solution to an issue facing you is probably available to Tier Two or probably only available to a professional earning six figures a year. You can then route your queries to the bank to get in front of the appropriate person with the minimal amount of effort expended on making this happen.
> You might think bank would hate this, and aggressively direct people who discover side channels to Use The 1-800 Number That Is What It Is For. For better or worse, the side channels are not an accident. They are extremely intentionally designed. Accessing them often requires performance of being a professional-managerial class member or otherwise knowing some financial industry shibboleths. This is not accidental; that greatly cuts down on “misuse” of the side channels by that guy.
Persistent mispricings can only exist if the cost of exploitation removes the benefit or constrains the population.
For example, this person[0] could have simply booked a United flight from the United site for 15k points. Instead the person batch emailed Turkish Airlines booking offices, found the Thai office that was willing to make that booking but required bank transfers in Thai baht to pay taxes, made two more phone calls to Turkish Airlines to pay taxes with a credit card, and in the end only spent 7.5k points for the same trip on United.
This may be an extreme example, but it shows the amount of familiarity with the points system, the customer service phone tree and the actual rules to get cheap flights.
[0]: https://frequentmiler.com/yes-you-can-still-book-united-flig...