Keyguyperson said
Just to put it out there, all but the strongest willed humans are easily affected by the whole mind control thing, along with specially altered cyborgs with artificial eyes.
Good to know!
All told, the control isn't
that strong anyway. I more or less used "charm person" as the guideline; it makes you consider the siren to be a very good friend as well as a bit of an authority figure, but that's about as far as it goes; they can't order you to commit suicide unless you're already the sort of person that would kill yourself if your best friend told you to. You can't be ordered to turn on your allies unless you'd already be willing to do that for a good friend, etc.
The only thing that's really especially concerning is that if the siren gives you a specific long-term order, that order will stick around in the back of your mind even after the "charm" part wears off, and you might find yourself doing things for reasons you don't entirely remember.