It's everything mentioned. It just sounds better to tell everyone that you're worrying about over-charging, than that you don't trust your customers and/or empl

It's everything mentioned. It just sounds better to tell everyone that you're worrying about over-charging, than that you don't trust your customers and/or employees, and also want to make sure there was no mistakes. It doesn't matter how these people are trained, or what they are told. They will still prevent theft, even if they think it's not their job. It's even better if they genuinely think they are helping customers (which they in fact do!) because that makes the attitude of everyone involved better. It doesn't matter that they don't catch many theft attempts. That's the whole point, that if they are effective at prevention, there will be no attempts in the first place.