Totally agree. "Never"? Yeah, I wouldn't have a problem going to see a movie without a friend on a different night. But, I have to admit, when we're all sitting around together in my living room, and someone says, "Hey, let's go see X", if someone said, "Nah, let's not", we wouldn't leave that person at home. We'd just find something else to do.
No disagreement with any of this. But when one player says "Let's skip the desert travel", we don't go back to it next week when that player stays home, we skip that desert travel entirely, right? Now, if that player says "I don't want to play Dark Sun", we might very well have a campaign to play Dark Sun without that player. Just another example of the difficulty getting a perfect analogy, really.
By and large? Nothing until the PC's do something. The PC's are pretty obviously not from the city, and are too small in numbers to constitute a serious threat, so, why would the besiegers even notice them?
If the PC's try to walk past the siege and enter the city, something will happen. If the PC's try to pass through the desert to get to the city, the nomads do something. The only difference I perceive in this regard is that the nomads will likely see the PC's first, while the PC's will likely see the encamped siege first.
Fair enough. So, now the siege is away from the city. Of course, since the blockade is too weak to actually have any direct effect on the city (after all, that's WHY they're not at the city), they are no longer of any real use to the PC's either.
The nomad blockade seems similar, to me, then the siege that cannot get past the walls, which you felt had a significant effect on the city. One example given was the likely lack of supplies, resources, etc. within the city, which is what the blockade will also cause.
Wow. Are really going to get that pedantic? Really? What do you hire when you want to go attack a castle? That's what I want to hire. Whatever you want to call them, that's fine. However, cutthroats and whatnot are generally not what I wanted to hire.
You want to hire a small armed group for a short period to go and kill a sentient being they have never met before and has done them no harm. Armies attacking other nations, cities, what have you, normally get fired up (rightly or wrongly) about "the enemy". What fires up your little commando team to view that Grell as "the enemy"?
How do these choices not have player buy in? They are both providing means to reaching the goal. Both have pros and cons. The players now have a choice to make. What's not bought in about this?
They are choices of obstacles to hurdle between us and the goal. "You must cross the desert to get to the city in the desert" seems perfectly reasonable to me - it is a necessay step to reach the city. Adding in "or you can play out service in the Pits of Gehenna to persuade a demon to teleport you there" doesn't seem to relate significantly more to the goal in the city. As well, having a map of the region, the players can choose to traverse the desert or not. That demonic bargain seems closer to a GM breadcrumb than player agency to me.
But we have to assume a lot about the scenario. Random transport to the middle of a wasteland seems very different from "players set goals which include obtaining something from the city in the desert". I'm not sure the players had anything to do with deciding they would go off plane to this location. A game made up of a steady diet of the PC's getting blasted from location to location by what (at least to them) seems nothing more than "mad wizards engulf you in chaos" would get pretty stale pretty fast. The players have less choice than if they are in some organization where their superiors assign tasks they must carry out. At least there, they make the choice of staying allied with that group or leaving. If leaving is a "they kill you in your sleep" event, we're back to "no meaningful choices". If the players made the choice to ally with the organization, now it's a consequence of their choice.
I am coming around, I think, to your note that, knowing little or nothing about our hypothetical group, specific examples are very difficult. When one of us provides an example, the other incorporates it in a backstory that modifies or even reverses its meaning. Is there a point to more examples?
Anything is better than just parachuting them into the desert cold without any buy in at all and then expecting them to interact with every carved stick the DM lays in their way until they finally stumble around long enough that the DM will let them get to their goal.
Here, I think, we're off the railroad and into the rowboat (Celebrim's term). The players lack any basis for choice. My answer in this instance would be, first, an evaluation of character resources. Do we have , say, divinations that could help point us in the right direction? If so, let's use them to gather what intel we can. Assume we don't. We are surrounded by wasteland in all directions. I'm unclear wether we even know what we're looking for, but if we do we don't know what direction it is in. Can we gather any more info? Could we use Flight to get a longer view and see something - anything - differentiated in the featureless wasteland? No. I'll suggest, as player and character, I'm getting frustrated here.
So, we have no good options, and no apparent means of locating any. In character, it's looking pretty hopeless. We can sit here and hope to be rescrue, or pick a random direction and hope to find something. Rescue seems unlikely - let's go. What resources do we have to move faster? If Centipede is one, let's use it. As a player, same two choices. Unlike the PC's, I trust to the GM having a plan beyond "now that they are in the wasteland, they will wander until they die". But I'm likely to say "well, with no intel on the best direction and no way to get any, pick a direction at random and let's go". That said, I think I'd (player or character) be looking to interact with anyone or anything that might communicate some intel to me. Wandering scorpions, no. Wandering nomas, yes!
Now, here I do find myself, at least in part, coming to your thinking. If this seems an unusual event for the GM in question, I am still prepared to roll with it. I might, depending on the history and my own mood at the time, complain about the situation and express my hope that the rest of the scenario is a bit more "players planning" and a lot less "mad wizard blasts you throughout the planes".* [see ASIDE below] If this is the first scenario with a new GM, I'd feel more nervous, and a steady diet of similar setups would likely mean it's time to find a new GM. So, put me in that context, and I might well get shirty with the GM too.
* [ASIDE] I am recalling a game where we did spend some time balsting from location to location to gather the pieces of some artifact. I guess by agreeing to be so linked, however, we at least chose to be blasted from location to location until we collected all the pieces.
