So far the facts are so uncertain that we still don't know if the guy was an employee, actually was the guy she saw in the employee bus, went through normal security or who decided why to divert to JFK. Rumors are the very senior captain had turned in another crew in London earlier for misconduct on a crew bus going to the hotel. LAX has a procedure that lets crews go directly from employee parking to flt ops. If he was an employee he could not get his passport checked and his authorization to board the flight without first being checked on the unsecure side. I guess he could then park his car in the employee lot but dought it. It doesn't sound like this was a security threat. Maybe just a bit of investigation would have solved the dilema. He bought a normal ticket so may or may not have been an employee. Sometimes employees buy normal tickets, especially if they are on personal business or want a confirmed seat.
Guess we will have to wait and see why this all happened. The captain reporting crew member misconduct is only relevent if revenge was involved.