Carnegie Hall has tapped an architecture firm run by the son-in-law of its chairman, Sanford Weill, to design its $150m expansion. “Carnegie officials said they were impressed by a previous project by his firm: the design of the well-regarded new home of Alvin Ailey American Dance Theater, where the chairwoman is Mr. Bibliowicz’s mother-in-law, Joan H. Weill.” Ethical questions abound, and Carnegie Hall is being forced to defend its decision publicly.