There’s a cute tradition that, if you’re having a personal audience with the Pope, you buy a white Papal zucchetto and he’ll trade his for yours. That way, you get a personal souvenir of your meeting (albeit a costly one ... I’m sure a Papal zucchetto at Gammarelli’s doesn’t come cheap).
Thanks for the explanation.
It’s entirely characteristic of Ratzinger that he honors this innocent custom notwithstanding any private opinion of it that he may have. Like the red shoes and the camauro and all the rest. Because it isn’t all about him.