I read George Weiss, a former Yank GM, thought it was undignified. From The Team By Team Encyclopedia Of ML Baseball: " As an expression of their enthusiasm, [Mets fans] began to bring posters and banners to the ballpark, some made out of bedsheets. At first, ballpark security quickly removed the banners under direction of George Weiss whose Yankee sensibilities were stunned by this undignified behavior. However, under pressure from the press, Weiss relented, and eventually the practice of displaying banners at the ballpark became encouraged. The Mets even initiated MLB's first ever Banner Day." This book also says the 73 Mets were world champs, so......