iserith
Magic Wordsmith
I don't even know if it's a case of a DM making a bad call. I mean, how can we say with certainty when the DM fails to convey information versus when the players fail to absorb information? I don't think there's any way to say for certain, except in the most extreme cases one way or the other. Usually, it's some combination of the two things.
This is why I'd adjust rather than either allow play to stall out, or to address the issue. In the event where there is a clear error on my part as DM, sure, I'll acknowledge it and correct it if needed. But if it's uncertain, then addressing the issue may just make a bigger deal of things than needed.
And, this is not a tool just for instances like this. As I mentioned in another post, and one which I think you said you'd be okay with, I switched the motivation for a NPC, changing him from a victim to a willing participant in some evil shenanigans. The idea was something one of the players mentioned off hand during play....and based on the reaction of other players, it seemed an idea worth pursuing.
Also, inspired by other games, I'll sometimes establish fictional elements on the spot based on the results of a PC check, adjusting severity based on the result of the check, or something similar. So when the player makes a stealth roll and just misses his target number, I don't have the guard notice him immediately....but instead I have another guard show up, and then the PC will need to succeed on another check, maybe with disadvantage this time, or a higher DC. I'm not worried about the roster of guards....I just add one.
All this is to say that this method (for lack of a better term) isn't just about ensuring that the PCs can progress along the story track, or ensuring they don't fail. It's got a variety of applications for all game styles and overall the goal is to maintain quality of play at the table.
Yeah, bear in mind, I know why you guys do this stuff. It's just some people hate it, and it's worth trying to understand them better in my opinion.