Nodisarm is not the same as cursed. What you posted works only for removing cursed weapons and maintaining the cursed attribute to it. Regarding a nodisarm weapon (think humansunder, defiance, mel-kartha, etc), one can simply remove them like any other weapon with complete ease. But, they can never be dropped via strength loss, disarm, boiled leather shield, fumble, or anything else similar in design. The -only- way to remove a nodisarm weapon is if the wielder decides to remove it or use another weapon as replacement.