Lanefan
Victoria Rules
I agree this is awful.I have played with D&D GMs whose response to that sort of thing is to shut it down - ie the inquiries produce no new information or options, all the potential informants remain silent, etc. I personally regard that as terrible GMing.
I don't agree that this is awful, as long as there's some underlying logic to it all - maybe the PCs just happened to take the long way around to getting the info they really needed.I have also played with D&D GMs who don't shut this sort of thing down but string it out endlessly - leads lead to leads lead to leads lead to session after session of trying to "find the plot". I also regard that as awful.
I think the GM should take it seriously, and even if she already knows from her notes that the old postern was bricked up years ago, play through the PCs investigations until they learn this for themselves.To relate the above to the example at hand: if the GM narrates the guards, and hints at or foreshadows the sewer, what happens if the PCs start searching for a hidden postern they can enter through? I don't think there's a single best answer, because it's so contextual. If it looks like the players are themselves trying to string things out, or squib in some fashion, because they're having trouble screwing up their courage to try and enter the castle, then as a GM I think it can make sense to force them to confront the choice: Come on, people, what's it going to be? The gate, or the sewer? But if there is something genuinely going on - eg one of the PCs is an engineer or architect and so has some special interest in finding and exploiting the postern - then I think the GM would do better to take it seriously and see where it goes.
And at that point maybe the PCs come up with a bright idea as to how to get through a bricked-up postern in a way that doesn't raise too much fuss; and if they do (and if things work out for them) that's cool! But it won't be without risk...

Thing is, to some people those are the same thing.If the idea that the player has is genre and gameplay appropriate, then cannot be made to work seems to mean doesn't fit with what the GM had in mind. This is what I am focusing on; and I am saying that, in general, I think it can make for a bad play experience. Because it pushes play towards working out what the GM has in mind rather than engaging and following the fiction.
The fiction is in the GM's mind, thus working it out is simply another step in engaging and following said fiction.
There's three pillars of play - 5e codifed them really well - and one of those in a way is almost completely a matter of puzzle-solving; that being exploration (and exploration also includes investigation and info-gathering).(To be clear: if we're playing OSR-ish/"skilled play" and we're talking about puzzling out the riddling statue, or the room of trapped demi-gods, or similar than it's a different kettle of fish. But most of this thread doesn't seem to be about that sort of play.)
Downplaying or removing puzzle-solving largely guts one of the three pillars. Why would anyone do this?
Sometimes social interaction also involves puzzle-solving e.g. the riddling statue, but it's less common there. Combat itself rarely if ever involves puzzle-solving, though the pre-planning and run-up to it often can.