No, you are wrong--new coaches sometimes don't honor. And if you go Ivy, every year a number of kids don't make the grade....literally.
Not just Ivies. Two girls didn't make it through admissions for the class that is freshman this year at Duke and 1 at Stanford. Probably more I don't know about elsewhere. Need to hit the ACT/SAT scores outlined, GPA, and number of AP/Honors classes at the top academic schools.
Exactly, terms of offer were not met, of course there will be commits that don't live up to the agreement and the commitment is lost, that sorta goes without saying.
