Prep School Students
As the parent of one prep schooler and adviser to many, I know for certain that there is no way that prep school students have an automatic advantage. This is made very clear when one considers how much colleges seem to weigh having first-generation applicants. Prep schools are very good at providing opportunities to students, particularly in terms of demanding college-prep courses. However, it is up to an individual student to take advantage of those opportunities, and that is what the colleges will assess. There are some cases where prep schools send consistently high quality candidates to colleges, and admissions officers will recognize or expect a certain caliber of applicant.