No, legally the theatres have no right to block the sidewalks. Try and find an NYPD officer to enforce that however, and you'll be looking a long time. Some theatres handle this better than others. Some security staff think they own the sidewalk, and that is wrong. I live opposite the Hirschfeld and when Daniel Radcliffe was there it was bedlam every night and those of us who live on the block complained often as there was no protection from the traffic and the crowds and it was a dangerous situation -- the local precinct finally brought officers in every night to stop traffic when need be. I think its one of the great things about New York for locals and tourists alike to be able to see famous people just by walking out your door.