Chronologies Vs. Plots

In a discussion on Dreams In The Lich House, we are playing with conceptions of sandbox and railroad style play. As usual, some people are operating from a flawed (in my opinion) understanding of sandbox play and talking about how a "pure" sandbox is this or that thing which is not necessarily so.

Anyway, I started to discuss the difference between a timeline and a preconceived plot:

A timeline does not place any restrictions on what decisions the players can make. The players may choose to confront the mastermind of the timeline or they may choose another route to success. There is no pre-scripted scene involving a necessary confrontation between the mastermind of the timeline and the players. A preconceived game includes the assumption that the players will maneuver their characters in such a way that the mastermind will be confronted, and that scene must occur to resolve the situation either positively or negatively.

I also made the following statement:

Some examples of techniques that I think are mistakes in roleplaying, but which are useful in other entertainment media (and this is not exhaustive): "Boss monsters", cutscenes, climaxes, act structures, and so on. This, by the way, does not mean that in retrospect some of these things might [edit: I meant "won't"] occur, or be imposed on the narrative of the stochastic events, but rather that using these concepts as organizing principles is a mistake.