It's pretty easy to envision this. Say something he did caused a pallet not to be included on a manifest and it had to go out on another flight when a human at the other end noticed it was missing.

It probably comes down to time spent trying to track whether or not he did something malicious and other investigative processes necessary. Put a few security experts or a consulting firm on the case for a year and it gets quite expensive. Also if they found out he compromised sensitive information and had to change plans or reschedule something then expenses start racking up.