EzekielRaiden
Follower of the Way
I would not, personally, call that a form of railroading--if the GM is open about their actions. "Guys, I understand you'd like to do that, but <explanation>". For example, let's say they want to destroy the Red Wizards of Thay. That's...a really, really big task. Even if the players fail, that's kinda reorienting the entire experience around just this one thing, which is going to be a LOT of Wizards, and going to involve a lot of pretty icky scenarios because the Thayans love them some slaves. If I, as GM, were running an FR sandbox campaign out of Waterdeep and the players said "We want to go destroy Thay!", I would level with them: "I'm deeply, deeply uncomfortable with the kind of society Thay is. I find its leadership almost universally repulsive, and I find its practices barbaric in the best of cases. I don't think I could run a game focused on Thay, even if I really wanted to...which I don't. I absolutely understand and appreciate your desire to destroy Thay, because it's absolutely monstrous, but I just...don't believe I could make that a fun, thrilling, worthwhile experience. I would be miserable running it and I'm pretty sure you'd eventually notice. Is it okay if we look for something else to do instead? The Zhentarim also practice slavery, would that work for you?"To expand on this, I also think you can have a non linear campaign and still have railroading.
Take the forgotten realms for instance (as a published setting i know well) - maybe the players want to try and get one of the characters to become a Lord of Waterdeep. Maybe they want to forge a new trading route through Anaraouch desert, or set up a smuggling route in the sword coast. Maybe they want to try and found an eleventh town in Icewind Dale, or some sort of outpost for forays in Chult. They may want to try and destroy the Zhents, or the Harpers, or the Red Wizards.
If a DM running a sandbox campaign in the Realms says no to players attempting the above, then I feel that is railroading, as forcing the players away from what they want to do to perhaps more run of the road general adventuring / dungeon exploring.
Again, the core difference is that this is genuinely engaging in a dialogue. It's letting the players actually make informed decisions. Railroading doesn't allow that, either because it's just ham-fisted denial, or because it's more subtle manipulation (or coercion).
Well, at least for myself, the issue lies in whether those odds are determined in a legitimate, fair way. Again, the example of "sure you can do it, but only if you get three nat 20s" is something I use as a very obvious bait-and-switch "yes". That is, the GM who does that is saying they "allow" something, but then ensuring it actually or functionally cannot happen, which is...just the same as saying "no" but with more steps. Three consecutive nat 20s is a 1 in 8000 chance, meaning functionally never going to happen, certainly not on command exactly in that moment.Where someone like Permerton may differ to me, is that if a DM says yes to the above, but is the one determining what is required and odds of success for each step, that Pemerton may consider that railroading still, which I dont. Yes, is different level of agency to a situation where the DM and players together determine possible steps and odds of success, but no more railroading to me, though I think either approach would work, especially if everyone has reasonable understanding of the world or access to get it.
This doesn't mean that all possible difficulty assignments cash out as railroading. Perhaps the players are genuinely trying to do something difficult; that's not unusual in the slightest. But the GM needs to set reasonable, context-appropriate difficulty, even if it's an action or effort that isn't particularly to their taste. Some of the time, the only reasonable answer is "I'm sorry, you can't do that", too, to be clear--but the GM should always explain why, and should be patient and understanding and genuinely listen to player input, because it's always, always, always possible to be wrong even when you're very sure you're right. God in Heaven, do I know that feel.