I've read that Nieman Marcus denies that story, and in fact posted their actual cookie recipe on the web.
Years ago, when I was in college, my first MIL to be was bridal manager at the Ft. Worth Neiman's, and I often hung out their on Saturday afternoons.
Their chocolate chip cookies were orgasmic. They also had wonderful strawberry jam.
I had so much fun at that store.
One day, the manager of fine jewlery showed me how he treated the millionaire's wives. He took me into a locked room with an armed guard at the door, opened the safe, and let me try on all kinds of fantastic diamond jewelry, including a yellow diamond solitaire ring that almost hid my knuckle.
They did any and everything to please their customers, and treated everyone who came in the same, because a pauper one day, might be a millionaire the next.
Years later, when I started my own business, I remembered that rule, and I loved seeing the Lincolns and Cadilacs out in my parking lot next to the old beat up clunkers.