[adotbacon]

I think surfacing additional information would help increase confidence in the system when it raises a problem.

For example, keep a running passengerCount (or rather display it since it must(?) exist). If someone has a copied pass, their screen can show: Current Passenger Count 10 This Pass Last Scanned at 5

If the fraudster & legitimate passenger are back-to-back, that might add some confusion for the agent so they'd need a good way to display this. They can call out to the last person to come back to clear up confusion.

If the fraudster was much earlier, they'd have to go find them. Maybe take a picture of each passenger during pass-scan.

Or simpler: this would be simplified by using Steffen Method boarding [1]: you should know exactly which seat matches a given passenger count number.

[1]: https://en.wikipedia.org/wiki/Steffen_Boarding_Method