The Free On-line Dictionary of Computing (30 December 2018):

lace card
ventilator card

   (Obsolete) A punched card with all holes punched (also
   called a "whoopee card" or "ventilator card").  Card readers
   tended to jam when they got to one of these, as the resulting
   card had too little structural strength to avoid buckling
   inside the mechanism.  Card punches could also jam trying to
   produce these things owing to power-supply problems.  When
   some practical joker fed a lace card through the reader, you
   needed to clear the jam with a "card knife" - which you used
   on the joker first.

   [Jargon File]