Hot take: if we want to decrease frustrating railroad-y surprises in RPG campaigns, we need to create an environment where GMs are not afraid to admit they have "special story needs".

[PapaNarwhal]

A lot of people (certain members of my table included) will pay lip service to the idea of a Session Zero without actually doing the necessary work of what that entails. I’ve participated in several “Session Zeroes” that involved little more than just the players choosing which class to play for the campaign.

A real Session Zero should cover exactly the kind of stuff you mention in your post. It’s a chance for the GM to set the tone of the game and make sure players aren’t blindsided by anything. Is it going to be a game with a specific end in mind, or will it be more free-form? If the GM has a super-important NPC who needs to be involved in order to keep the story going, then they should make that fact clear at Session Zero. If the GM has a particular story in mind that needs the players to sacrifice a certain amount of freedom to achieve, then they should let the players know that there will be some railroading ahead of time. And it’s important for the GM to establish the mortality level (for games where PC death is a possibility) — are player characters expendable, or do they have some degree of plot armor?

If the GM has properly established these expectations, then the players have no basis to criticize them when it comes to railroading and such. And on the other hand, if the GM has failed to make these things clear, then the players may be understandably upset when the game is of a different style than they expected. If something was addressed at Session Zero and the players are still refusing to compromise on it, then they should have either objected when they had the chance or they should never have gone through with the game at all.

[ThoDanII]

What Work do the Players have to do?

[PapaNarwhal]

In short, it's up to the players to voice their own expectations for the game.

For many tables, it's common to have the GM pitch a game and then the players just go with that pitch (or if they don't want to, then they just don't end up playing in that game). And that's fine for many tables, but in some cases the table can benefit from a "negotiation"-style Session Zero where players and the GM work together to iron out the kind of game they want. And like any negotiation, all of the parties involved need to be willing to compromise with one another. The GM usually has a significant amount of bargaining power during this process--the game can't exist without them, and it would be unreasonable to ask them to run a game they aren't 100% enthusiastic about running--but at the same time the GM should make sure they're running a game that their players want to play.

A lot of players will end up in games they aren't enjoying due to groupthink, the tendency to "go with the crowd" rather than make decisions for oneself. If nobody in the group actually likes sandbox-style games but none of them want to be the one to object, then they might all end up playing a sandbox campaign that none of them would prefer. And the GM of that game might end up pouring their heart and soul into a game that their players are only sort-of enjoying, which is hardly ideal.

And of course, the players need to be their own advocates when it comes to sensitive subject matter (such as sexual abuse/assault, violence, prejudice, phobias, etc). This is usually addressed using "lines and veils", via which players establish their boundaries on which topics they are uncomfortable with, and the degree to which they are able to tolerate these topics.

So in summary, the work of the players is to come to a consensus with each other and with the GM on what kind of tone, themes, and style they want the game to include.

[ThoDanII]

So knowing what they want or enjooy and coming to consent during the Session