The problem comes when the FA package is borderline-not affordable enough to be comfortable, but enough offered so that the student could scrape together the money to attend if necessary. An ED student, not able to compare offers, has no way of knowing if a low FA offer is the best they’re going to get. The danger (and everyone’s nightmare scenario) is that a student turns down a FA offer from their dream school, only to find that the offers at all their RD schools are worse.