In my own experience of family research is that decisions to free the slaves were a direct correlation of the straight line distance from the advancing Union Army.
Stories from the little ladies usually go like this: Great grandmother decided to return to the plantation, but freed all of the slaves before she started the journey. The slaves begged her to take them with her, but she explained that the situation made that impossible. TRANSLATION: The Union Army had arrived, freed the slaves and great grandmother loaded up a wagon and got out of town as fast as she could go.
Yeah. I hear you loud and clear.