My response is: "What is the information you seek?"
Every admissions staff is organized in the way that makes the most sense to their organizational goals. Generally, the Director of Admissions (for any school, let alone the top 15) is not going to be available to answer general questions. It's a simple issue of supply and demand. The mere volume of questions posed to admissions offices is enormous.
If your question is a general question, see if you can find the answer on the school's web site.
If you are just trying to get your name in front of the Admissions staff so they will know your name, don't do it. Those efforts are very transparent, and they waste the valuable time of the admissions committee.
If you have a unique question or situation, then you can reach an Assistant or Associate Director, and they will do an excellent job representing the program and answering your questions.
In fact, I recommend that all serious applicants develop a relationship with one of the staff members (Assistant or Associate Directors) so that you can have a point of contact.
If I can help further, let me know!
15 Years as Director of MBA Admissions - Now Working For the Applicants as the MBA Admissions Coach
Wendy Flynn is the MBA Admissions Coach, providing comprehensive MBA admissions consulting services. As the former Director of MBA Admissions for 15 years at a top-30 MBA pgoram, Wendy holds deep expertise in admissions issues for Full-Time, Executive and Professional (Part-Time) MBA Programs. Through her blog, MBA Expert Insights, she brings the view of the Director of MBA admissions to MBA applicants and others.
MBA Expert Insights Blog: http://www.mbaadmissionscoach.com/blog/
Member of the AIGAC, Association of International Graduate Admissions Counselors