That's a red herring. It's not the absolute number of staff in a particular supermarket that we're talking about, but the ratio of people employed to work done.

That's a red herring. It's not the absolute number of staff in a particular supermarket that we're talking about, but the ratio of people employed to work done. Using their lowered operating costs to expand their business doesn't negate the fact that their checkouts are operating with less human labor.