I am struggling to understand how someone could think it was acceptable to an airline to have an invalid credit card on file in order to hold tickets and the fares. And then complain it took 3 years for the airline to detect the problem.

With over a hundred million passengers annually it takes time for unusual behavior to be detected.

I would not like my clients to give me a deposit by check on a closed account so I block out time for a project but they want to continue to shop around or change their mind while I hold the time for them.

How could this behavior be rationalized?