The dying art of knowing where to queue?

One of the staff reported a curious incident, which occurred in a big store the other day. He went up to the checkout in the food hall and paid for his “5 items or less”, then the young lady on the till pointed behind him and told him that, actually, that lady was before him. My staffer looked over his shoulder and saw no one. Then he realized that the cashier was pointing at a woman standing a good three yards from the till area.
    “Actually,” he said, “I did wonder about that, but then I thought that if she’s standing right over there, she can’t possibly be in a queue for your till.”
    To which neither of the women concerned had an answer.