Developing a bit on my previous post, consider two different sorts of hidden information.
In a single-character-per-figure wargame, we might draw a river or a muddy area on the map. It is quite reasonable for the referee to posit that the depth of the water/mud is not ascertainable merely by visual inspection: the player who doesn't just want to chance wading/driving through has to declare some action whereby their character can learn the depth, and this creates a risk (eg of being grabbed by a crocodile lurking in the water, or triggering a booby trap sitting on the river bed, or whatever).
Contrast: the GM describes the scene, but deliberately omits something from the description (eg the presence of a diagram drawn in the dust on the desk; the absence of ashtrays from a room that smells of cigarette smoke) with the expectation that the players will intuit that there is more relevant stuff that their PCs might be seeing, and then ask the GM to fill in those further details.
The former fits within the paradigm of Gygaxian skilled play. The latter has in my view little or nothing to do with skilled play, and again is a development that is distinctive to RPGing, and is about how the GM maintains control over the dispensing of fictional details, based on particular, enculturated expectations about how players will approach the game. (Including by asking the GM to fill in more details that *don't require their PCs to actually perform actions besides continuing to look at what is in front of them.)
In a single-character-per-figure wargame, we might draw a river or a muddy area on the map. It is quite reasonable for the referee to posit that the depth of the water/mud is not ascertainable merely by visual inspection: the player who doesn't just want to chance wading/driving through has to declare some action whereby their character can learn the depth, and this creates a risk (eg of being grabbed by a crocodile lurking in the water, or triggering a booby trap sitting on the river bed, or whatever).
Contrast: the GM describes the scene, but deliberately omits something from the description (eg the presence of a diagram drawn in the dust on the desk; the absence of ashtrays from a room that smells of cigarette smoke) with the expectation that the players will intuit that there is more relevant stuff that their PCs might be seeing, and then ask the GM to fill in those further details.
The former fits within the paradigm of Gygaxian skilled play. The latter has in my view little or nothing to do with skilled play, and again is a development that is distinctive to RPGing, and is about how the GM maintains control over the dispensing of fictional details, based on particular, enculturated expectations about how players will approach the game. (Including by asking the GM to fill in more details that *don't require their PCs to actually perform actions besides continuing to look at what is in front of them.)