Egad, it be better avoidable. It was stated that stuff was optional long ago.
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The first time I had that option it was not unavoidable, and it was on the ground. After that I have not had to (you can run from ship battles).
I was given the option at level 15 (though I had saved a level up or two at that time). I think it is more story plit driven and based on your lightness/darkness.