You can't lump all Ivy's (or schools from any conference) together. That being said, if you daughter had offers from some Ivy's I am sure that you are aware of how the Academic Index works. If an Ivy's top recruits are at the lower end of the Index the coach will have to bring in recruits that are at the higher end of the Index in order to balance out the index average. Those recruits may not be high end lacrosse players but they will have crazy high grades and test scores. It has nothin to do with $$ or being a legacy, it has to do with their Index score. Other high end Academic schools have different ways to get players into school, Duke has a certain number of "slots" that they can use to bring in players with grades below the normal admission standards. Northwestern can bring in whoever they want, every school is different but the bottom line is that the top recruits do not have to have the same grades as the recruits with less lacrosse / athletic ability. Not all recruits at Ivy's (or any conference) are equal, there is a wide range at individual schools and their is a wide range throughout the conference.
Very accurate and informative post. I'll just add that Northwestern can't bring in anyone they want, but their standards are well below any of the other more academic schools or even top publics (UVA, UNC, Michigan).
That said, they won't admit someone with a 2.5 GPA and 950 SAT. (not that she would be able to keep up at the school).
UVA, UNC & Michigan all have a very specific number of slots available. NU does not have a hard number and yes they have significant leeway but they are extremely cautious if they believe a player will struggle academically.