Just a thought - what about being able to cast Dispel on certain charmed sailors to release them from their domination? They could either then turn friendly and help you or at least run away without forcing good characters to put them down.
Clarity would make more sense.
Either one, I would say.
You can charm-person them too but unfortunately that of course doesn't do anything other than making them stop attacking you, and you only. I always assumed their dain was too bramaged to be salvaged anymore, after all they have been through.
I always felt the implication was their free will had been subverted and brutalized by constant exposure to enchantments/torture, and by the magical will of the Harpy Queen - to get to whom you have to kill everyone else.
Integrating a complicated rescue script on one of the most popular quests in EFU seems like a bad idea.
If it ain't broke, don't fix it!
Not a fan of this as a permanent option, but a little DM flavor for certain related IG pursuits would always be welcome!
Of course this would be ideal, but trying to script this would be complicated, time-consuming and probably end up being buggy.
OFF WITH THEIR HEADS!