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.