Lawyers don't like to ask questions of a witness unless they know the answer the witness will give and can compel the witness to give it. Hillary Clinton, whose troubles with questions from the people are the stuff of political legend, is employing the reverse of this lawyer's rule: don't take questions if you don't have a good answer.
As Riehl World View explains that Hillary's take NO questions in an attempt to avoid further gaffes, like not knowing how many children her close, personal friend Benazir Bhutto had. (Answer: 3. Hillary's answer: 2)