I understand the resource constraints and why students/alums are used in a lot of cases, but from what I understand some schools only use their admissions staff.
I have to disagree that the purpose of a business-school interview should be to simulate a job interview. That's like saying that a job interview should simulate what you will do after they hire you. The purpose of a business school interview should be to inform the admission's decision.
If you were the dean of admissions at a business school, and you have plenty of resources (i.e. you had enough people working in admissions to actually have them read apps, and then interview all the candidates) wouldn't you rather have people walk interviews knowing a person's application so they can ask drill-down questions? An interview question could be something like, "So I know in your essay that you said you're interested in international development because of the work your father did in West Africa, but as I look at your resume I don't see that you have a lot of experience in this area, how do you plan on preparing yourself for this goal?" But in a blind interview, that conversation might go more like, "So what do you want to do with an MBA?" and then the candidate would have to go into all the details that could have been gleaned from a ten minute scan of the application.
3_underscore - When you say that an alum interview might not be fair because they don't like your face, I'm inclined to agree that a "blind" interviewer would be more likely to let bad chemistry in an interview influence their opinion of a candidate. Whereas I think someone who has read a candidates application will have more data-points and will be able to sort of contextualize things better.
Rhyme, you do interviews for your undergrad school right? What are your thoughts? Are you one of the horrible interviewers I'm talking about? (Kidding of course)