North Carolina’s Eastern Music Festival has canceled an appearance by Blair Tindall, whose provocative memoir, ‘Mozart in the Jungle: Sex, Drugs, and Classical Music’ is the talk of the classical music world. When organizers of the festival learned that concern about the book’s content had prompted another festival for young musicians to cancel Tindall’s appearance, the decision was made to cancel the July 5 talk. “We are concerned that some of the material might be inappropriate or confusing to a 14-year-old student.”