I tried this one at one of my first interviews with a faculty member, and it did not go over well. Guy gave me a very curt response, and then the stinkeye for the rest of the interview. I guess he considered it improper for an applicant to ask that of an interviewer. I reserved this question for students at my later interviews, with better results. Your mileage may vary.
There was one interview where I absolutely could not think of any question that had not already been answered by the website, the presentations, and the discussions with current students. I didn't want to ask something "just to ask", so I told my interviewer that the school had provided so much good information that I didn't have any further questions at this time. In retrospect, maybe I should have just asked something I already knew.