Like it or not Avman is right.....with one possible exception
"Have you ever witnessed how eager CC are to get off their a/c in the U.S.?
The issue of getting out is irrelevant. She should never have been left there in the first place. Bottom line: CC negligence, period. No blame on TSA or police as they obviously had to do their job and establish WTF was going on. 100% CC's (and thus the airline's) fault. Next case please."
As usual we don't have all the facts. However with what has been presented it does appear CC negligence. It doesn't matter what we think of the womman herself, a crew does not leave a passenger alone in the jet after arriving at the destination-period.
The exception is whether or not this was a set up and intentional where woman hid from the CC. That is unlikely but not beyond the realm of possibility.
Another thing that is "different" about flying for a living is that most of the time it is so routine. The same process over and over. However, when things go badly and all it takes is an introduction of some seemingly insignificant event or item, and the flight can go terribly wrong. Children flying alone left on jets after they should have gotten off ending up in cities they were never supposed to be in, people turning right instead of left as they disembark and falling out of a door left open for catering and ventalation, shipping things not allowed on aircraft starting a self sustaining cargo fire.................
SOPs, training and policy; much of it is developed because somewhere, sometime somebody got hurt or something was destroyed. It is often said flying regulations are written in blood. When we do not follow procedures we "poke at the tiger through the cage bars with a stick". Now what do you suppose the crew is going to tell their manager(s) to explain how this person was left on the jet? I would be very interested in thier side of the story!