No Myth rejects the need for this distinction in the first place, because pre-planned things cannot have influence on the game.
But thats not true... they just have to be introduced under certain conditions.
Edit: And honestly I think its still possible to appear to be following a No-Myth agenda but direct play (at least in a general sense) using pre-constructed notes...
Can I make the sister just choose not to help her brother...no
Can I make the difficulty so high it effectively has a much higher chance to go that way... yes (at least in some games).