What automation Southwest had still required a lot of manual intervention on a regular basis. E.g. scheduling still required manual intervention if a flight didn't go as planned. Luggage was almost entirely manual process (weight and balance, hand written tags, etc) up until very recently. Now it's a mostly manual process. So on a day to day basis things can be brute forced, but when something like scheduling goes tits up and leaves you with a giant mess of luggage you're left to clean up the mess in the most tedious way possible.
I imagine someone manually changing the flight manifest by clicking a delete button on each passenger and crew member, and waiting on a database save and gui redraw after each action. Complete with major timeouts and concurrency errors due to the massive spike in traffic caused by the storm.
