<p>Interviews are non evaluative. Alums won't send a letter to princeton saying you sucked at your interview. However, if they get really excited they may write to the admissions office about you - but that isn't guaranteed to boost your chances.</p>
<p>Interviews are not required by Princeton admissions, and applicants that do not get an interview are not penalized in any way in the applicant pool. As mzhang23 said, interviews can only help you, and will never hurt you. I guess thats like saying a bad interview is like one that never happened in the first place. </p>
<p>I would say that the majority of Princeton students get interviewed, but there are plenty of people who did not get one. If there is no interviewer in your area, or you cannot arrange an appointment before the application deadline, again it is not a problem. </p>
<p>Actually in my case my high school arranged for a lawyer who is a Princeton alumnus in the town where my school is situated to interview me. I never had an alum call me to make an appointment.</p>