This could also apply to the way airlines see passengers. In my experience, passenger information is scattered across different systems and representation. One

This could also apply to the way airlines see passengers. In my experience, passenger information is scattered across different systems and representation. One system tracks the reservation itself, which has information 1 or more passengers. Another system tracks the fare and various feeds paid or due. Another tracks check-in status. Yet another has seating information. Bags checked live somewhere else. There's not a common key. There are of course confirmation numbers (those 6-character codes), but only after a reservation is confirmed. If a person has a frequent flyer code, that's another key. As the passenger moves through the system, each different subset of attributes is attached only to the system in which it lives, and cross-correlating a passenger across systems is done in numerous ad-hoc ways. The customer service folks have a lot of tribal knowledge, and if you happen to get an experienced one, they can really smooth the way. During the pandemic, though, a lot of people left the industry, and a lot of knowledge just walked out the door.