Imaro
Legend
Well, it's a bit hard to tell what's going on, in terms of table decision-making, until we know:
EDIT: I've seen @Ovinomancer's posts in response to this example. We're not carbon copies but I think nevertheless are in broad agreement. His point about what follows, in the fiction, from getting to the top of the wall (eg hiding as opposed to being discovered by a hitherto-unnoticed NPC the GM has secretly recorded as present) is particularly well-made.
- Who narrated the existence of the wall, and why - ie via what process and according to what principles?
- Similarly, who narrated the existence of the guards?
- Similarly, who established that there is an alley for the guards to look down?
- Perhaps most importantly, what has brought it about that the PC is in this place trying to achieve this particular thing?
What does any of this have to do with who decided what happened? Scene framing sure but the resolution of action in this example is determined by the roll of the dice... so the DM couldn't have determined everything that happened.