Two interesting articles related to this but not exactly the same dinner party story -
https://www.brookings.edu/blog/brown-center-chalkboard/2019/03/15/inside-the-ivy-league-college-admissions-process/
http://www.insidehighered.com/admissions/article/2019/03/25/brown-faces-questions-about-benefits-it-has-provided-legacy-applicants
Looks like some things are changing, though.