2006 New York Code - Negligence Contributing To Alteration Or Unauthorized Signature.

 
  Section 3--406. Negligence  Contributing  to  Alteration or Unauthorized
                    Signature.
    Any person who  by  his  negligence  substantially  contributes  to  a
  material   alteration   of  the  instrument  or  to  the  making  of  an
  unauthorized signature is precluded from  asserting  the  alteration  or
  lack  of authority against a holder in due course or against a drawee or
  other payor who pays the instrument in good faith and in accordance with
  the reasonable commercial standards of the drawee's or payor's business.