Isn't pretty much anything the PCs are asked to do by anyone a "quest"? If the bartender says "Hey, could you clean my pantry? I'll give you 5 silver", it's technically a quest.
I'm not sure how an entire campaign could avoid having any quests at all unless the DM refused to have any agency in the game at all.
I'm trying to think how many episodes in my 4e campaign (6+ years, currently 29th level) have resulted from NPCs making requests.
I can think of two.
The campaign started with the PCs meeting in a tavern (of course) and being recruited to perform a task (driving horses to market, I think) by a forester. The players knew I was using a module which at least one had a copy of himself. And they knew I had indicated that every PC must have a reason to be ready to fight goblins. So they knew that this was just a plot device to get the game moving. I can't remember what happened to the horses, but the PCs certainly never had anything to do with them!
The other one I can think of is a PC being tasked by his god to recover a lost artefact (which turned out to be the Rod of Seven Parts), but that was the player's idea so probably doesn't fit your definition of a quest.
A third one might have been when they went looking for the missing niece of the Baron, although it may be that they initiated that themselves - I can't remember now.
In any event, in a game in which the players are taking the lead, the GM's agency is in interposing opposition and driving towards conflict. Whereas the players provide the dramatic motivations for their PCs. This does not give the GM any lack of agency, and has nothing much in common with computing.
I guess I just like foreshadowing in my stories. I like stories that are unresolved but them pick up again later.
I think a lot of people like foreshadowing (maybe not [MENTION=66434]ExploderWizard[/MENTION]). But that is fairly orthogonal to the current discussion. It possible to generate foreshadowing without using the sort of heavy-handed style that the adventure you've described does.
Here is an example from my 4e game:
* The PCs travel temporarily into the past, and while there rescue a young apprentice from the mirror in which her crazed master had trapped her;
* Back in the present, the PCs see a series of family portraits on the wall of the Baron's hall - two of the women greatly resemble the rescued apprentice, although the one in the older portrait is quite a bit older than the apprentice was when she was rescued;
* The PCs learn that the older woman (the apprentice aged 50-ish?) was the Baron's grandmother, and that the more recent portrait is of his niece, who (i) happens to be engaged to marry the Baron's advisor, whom the PCs know to be a secret Vecna-worhsipper, and (ii) happens to be missing;
* The PCs track down the niece, thinking she's been kidnapped by undead and/or her fiance, only to learn that she is a necromancer who has accidentally revived Kas from torpor;
* The PCs defeat the niece, but save her from Kas's vengeance by striking a deal with him to track down the apprentice, who was the one who trapped him in a torpor.
When the apprentice first appeared in the game, the Baron's niece had not been conceived of. When I introduced her as an off-screen NPC, I can't remember if I had the idea for Kas's role or not. The idea that Kas would ask them to hunt down the apprentice emerged in the course of play, as the PCs negotiated with him.
Another less intricate example:
* The PCs meet a friendly duergar and accompany her to the duergar hold. On the way, the tiefling PC cautions them that trafficking with devils will be their undoing - like the tieflings, they are a dying race;
* A couple of sessions later the duergar stronghold is destroyed, along with many of its inhabitants, by forces introduced into it by the chaos sorcerer PC, who had (only slightly inadvertently) called upon Pazrael/Pazuz.
That one has irony mixed with its foreshadowing.
There is no necessary connection between foreshadowing and GM roadblocking, or similar uses of force, of the sort that you are describing in this module.
Isn't this the essence of virtually ALL mystery stories though?
Take for example: A murdered body is found. Who did it? The knife has a symbol that incriminates one person. But that person has no motive. Someone else really doesn't like the victim and has reason to see them dead. But they couldn't have done it, they were spotted across the house at the same time the murder took place. The clues don't seem to add up.
Then, one of the people involved messes up and changes part of their story. They said they were looking out the window but somehow they also saw someone else run out of the room on the opposite direction. Obviously, he is lying. Now that we know someone is lying, we know it is probably them.
But until that slip up happens, there's no real way to solve the mystery. There is just not enough information. The author of the story decides on just the right moment to reveal that last critical piece of information to let the reader or the watcher figure out the mystery.
I think in RPGing the notion of "just the right moment" has to be reversed. Rather than the GM withholding information or blocking the players "until the right moment", the GM should be ready to pull out all the stops at the moment the players put it all together and work out what's going on.
That's what makes it the right moment.