Maybe it's "Authored" vs. "Emergent"

[Satinavian]

No you misunderstand what I'm asking: Why not?

Because it is not my style.

Go back and see how my argument was that I don't run the game that way. And that that means that there are GMs out there doing stuff different from your description. Which means all your talk about "all GMs do X" or "this is the GMs job" is plain wrong.

That aside :

When is a DM allowed to do a thing?

when the group agrees

When is a DM not allowed to do a thing?

When the group disagrees.

The OP appears to define Emergent gameplay, as the players doing something that the DM doesn't expect.

Emergent gameplay - as per the OP - doesn't appear to be defined as the players doing what they want. I provided an earlier example of players entering a town for the first time, and declaring that they would head to the tavern. The DM expected this, and has an entire location and maybe a scenario or two for what happens inside said tavern, ready to go. But, it was the players' choice to go there. Nobody said they had to go to the tavern. But that's where the players went, because that's like...Where you go.

If the DM can pre-empt a players' decision, and plan accordingly; What is that? The players still get to make their free choice. The DM just knows what choice they're going to make. Because it's seven sessions in, the DM knows the players, their characters and their party dynamic.

That is actually an argument i made myself if you look back.

However, the ability of a GM to guess correctly what their players do, while potentially impressive, is still limited and there are always situations where the GM just guesses wrong.* The only way to make sure prepared scenarios really happen is by enforcing them aka railroading/removing agency.

In another thread I mentioned that I have a FROST plan for almost any hostile encounter I make. I pre-empt that my players, upon encountering a group of hostiles, will most likely do one of five things, and in the back of my head I can just sort of, wing it because I have the framework to draw upon. The players totally get a choice in what they're going to do. But I've pseudo-planned for what they're going to do, 99% of the time.

And what happens in the "1%" you didn't predict ? Do you lead them back to your plans (aka railroading) or not ?

Which is why to me, most 'Emergent' gameplay is basically the equivalent of 'Can I set fire to it?' ...Well no I didn't plan on you burning down the pub for no reason. That certainly is emergent. That sure is something I have to factor now. Emergent gameplay - to me - is effectively 'Irrational gameplay', and that may be one of the reasons why a lot of DMs might stipulate that players can't make Chaotic and/or Evil characters. The amount of 'Emergent' gameplay that a Choatic and/or Evil character can do, is near-infinite, and maybe that's a problem?

So basically the only way you can fathom players not acting as you guessed is them acting "irrational".

Do you even understand how belittling that is ?



* However, if you have players who like the scripted experience, they tend to guess GM expectation and follow them as well. This can lead to a quite robust dynamic where nothing ever leaves the rail becaue everyone always does their best to stay on it.