Note: This procedure requires editing a game file; creating a backup copy of the file before proceeding is recommended. With a text editor, edit the "LAi_location.c" file in the "\Program Files\Pirates of the Caribbean\PROGRAM\Loc_ai" directory. Locate the line:
location.noFight = "1";
...and change it to
location.Fight = "1";
You can now attack anything inside taverns, stores, prisons, loanshark's offices, shipyards, etc.