Seems interesting to me that NBC is the only network that has consistently used music on its newscasts (although I think there
was a time in the John Chancellor era when it didn't). I think it was Dick Salant who banned music from all CBS News programs
except "CBS Reports," where the theme music was Aaron Copland's "Appalachian Spring." ABC had had music during the Ron
Cochran and first Peter Jennings era; none during the Smith/Reasoner era; a theme song during the year Reasoner did the
news solo (1975-76), then none during the Reasoner/Walters era. When the theme for "World News Tonight" (quite possibly
the most recognizable news theme ever) caught on, CBS and NBC added music to their newscasts (NBC's "The Mission" by John
Williams also became fairly recognizable).
I do, however, remember an exception to Salant's edict at CBS: The "CBS Morning News" used to play a soft guitar piece, the
name of which I've forgotten (this was, I think, in the John Hart era in the early '70s). But then, Hart played by his own rules,
even doing the newscast in shirtsleeves until Bill Paley ordered him to put on a jacket.