The Collaborative International Dictionary of English v.0.48:

Scot-free \Scot"-free"\ [?], a.
   Free from payment of scot; untaxed; hence, unhurt; clear;
   safe.
   [1913 Webster]

         Do as much for this purpose, and thou shalt pass
         scot-free.                               --Sir W.
                                                  Scott.
   [1913 Webster]

         Then young Hay escaped scot-free to Holland. --A. Lang.
   [1913 Webster]