No doubt the CFA manager talked to her very nicely. They train vigorously to be pleasant with customers.
For her part, she should have complied. CFA dining rooms are always full of people, and that is a squishy thing to do in public uncovered.
She states she was not uncovered and totally exposed. According to her only the top part of her breast was visible. Which is plenty modest since you will see more than that if some woman came in wearing a bikini top.