I think that this understates the advantage of being a legacy. Admissions decisions aren't made by pitting one applicant against another in a March Madness bracket. Each applicant is evaluated on an individual basis; to say that legacy status is used to differentiate between two equally qualified candidates is a misrepresentation of the admissions process. In years past, legacies have enjoyed an acceptance rate of between 30% and 40%. This is a sizable advantage.
ABC News: Legacy #'s Strong, Admissions Down: Fair? Admissions should be blind to legacy status - The Daily Princetonian