DuckCorp Dico

Found one definition

1.                 From The Jargon File (version 4.4.7, 29 Dec 2003):
                   
   
   
                   
                     
   molly-guard
    /mol'ee·gard/, n.
       [University of Illinois] A shield to prevent tripping of some Big Red
    Switch by clumsy or ignorant hands. Originally used of the plexiglass
       covers improvised for the BRS on an IBM 4341 after a programmer's toddler
       daughter (named Molly) frobbed it twice in one day. Later generalized to
       covers over stop/reset switches on disk drives and networking equipment. In
       hardware catalogues, you'll see the much less interesting description “
       guarded button”.