In my opinion ships used in war should be able to be stolen. (ex: New Grands battleship) This way they cant just have floating fortresses that are impossible to defeat. Or atleast you can get onto a enemy ship (that is in a WAR only) and place TNT on it...
And i'll ask for kbrown again. Are ships that were stolen before the rule update free of this rule or do they need to be returned? *cough* android *cough*