Fairly positive that hair is static. You can just tell from Screenshots.
This. From the point of view of technical limitation I can see why they chose to lose something that would damage FPS for such a small return like this.
From a childish point of view I want to have my cake and eat it. I do think they could have made hair look slightly better - in the earlier pictures with the guy sneaking in the forest - the guys hair looks like a slimey blond slug has been glued to his head and neck.
Long hair is a nono for me, since it's seemingly attached to your characters spinal chord.