This episode's headline: Product Liability. The guests include RONALD GRAYZEL, Product Liability Lawyer; Sen. ROBERT KASTEN, Republican, Wisconsin; VICTOR SCHWARTZ, Product Liability Alliance; DAVID GREENBERG, Consumer Federation of America. Byline: In New York: ROBERT MacNEIL, Executive Editor; In Washington: JIM LEHRER, Associate Editor; LEWIS SILVERMAN, Producer; MARIE MacLEAN, Reporter