Player in the group here. Long post - my apologies!
The reason for my questioning of this interpretation is due to what I feel is a very inconsistent rule set for the hidden condition.
Perhaps I can illustrate my POV using some images:
https://drive.google.com/open?id=1yaCunMcue6tpquupPhYyBGokObmbz9zY
(link to a jpeg on my google drive - hopefully that works!)
Image has 4 sections:
Both scenarios count the walls/house as solid providing greater cover with no line of effect for precise sense to observe anything behind it.
Scenario A:
A-1 and A-2 refers to the situation in our game. The encounter occurs on a moon lit night with no torchlight (dim light everywhere). The player has previously spotted a group of enemies and ran behind a 2-story house and starts their turn from there. The enemies have not yet seen the player.
A-1)
Blue: Our player is behind a 2-story house and is hidden due to the enemies having no precise sense line of effect.
Green: In this alternate scenario, our player is out in the open with nothing blocking precise sense line of effect to the enemies.
A-2)
Dark blue: Our player uses Stride to move to the corner.
Green: Our alternate reality player uses Stride to move to the same corner.
Question:
Here is where my interpretation differs from my group.
I understand the rules as when there is no direct line of effect for a precise sense (aka, house corner counts as greater cover and has no windows or holes - the line of effect intersects the house wall corner) the blue player would remain hidden around this corner as the enemies have no line of sight.
For our blue player I argue that they remain hidden as per the RAW the conditions for being observed are not met - no direct line of effect, there blue player is obscured by a greater cover and the area is dim light meaning the player is also concealed.
I find nothing in the rules that claim the opposite as due to the dim light the player is concealed, the player has greater cover and there is no direct line of effect from the center of the player to any enemy.
For our green player they did not start out as hidden, and instead is observed but concealed to all enemies. Upon reaching the corner they are still observed, but concealed due to not having started in cover and making no attempt at hiding. If that player wishes to become hidden they must use an action to hide.
But, understanding your posts here the claim is that anytime you near a corner, regardless of concealment or type of cover, you are automatically observed by any enemy, regardless of line of effect as no attempt at sneak was made.
This I feel is wrong and not RAI or RAW - please help me understand why you say this?
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Scenario B:
B-1 and B-2 is a made up example to help me understand better. A guard is guarding a corridor and looking straight down it. It is bright light all throughout. The player is aware of the guard and wants to cross over to the other side. The player attempted to sneak to their starting location and attempted a seek and have located the guard using hearing due to them coughing.
B-1)
Blue: Our player has no line of effect to the guard but have heard them cough and is aware of them - the guard is hidden to the player and the player is undetected and unnoticed to the guard.
Green: Alternate timeline player is at the corner but has no line of effect for precise sense (sight) but can now see the guard due to using an unobtrusive action to peek around the corner. The guard is observed to the player but the player is undetected by the guard.
B-2)
Blue: Using Stride our player moves across the hall and end their movement one square in from the corner.
Green: Using Stride our alternate timeline player moves across the hall and end their movement at the corner.
Question:
My understanding of the rules is that both players start their turn as undetected and unnoticed and end their turn as hidden in spite of nobody attempting to sneak.
Should either player opt to use sneak the DM rolls a perception check vs the players stealth DC and if that fails both players end up as undetected and unnoticed.
But, if I understand all of you correctly, you would say that the green player starts out as observed due to standing at the corner of a cover and end as observed for the same reason.
The blue player would start as undetected and unnoticed but would end as hidden but not unnoticed.
The green player can attempt to first hide, then sneak across to achieve undetected but not unnoticed. The blue player would only need to sneak to achieve the same result (however, due to halved movement would not make it that far and thus end up observed and out of cover).
TLDR; I see no difference in the two scenarios as the requirements for hidden are still maintained in both scenarios - in spite of having made no attempt at stealth since the key factor is line of effect for primary sense not being achieved in either scenario at the end of a turn.
However, what is written here is that this is the wrong interpretation of the rule and standing at a corner of any type of cover always results in being observed as long as a player can observe an enemy, even if there is no direct line of effect between the two creatures?