Lanefan
Victoria Rules
There's a difference between a character reacting to what it perceives and a character knowing why it is perceiving that thing.If the character does not know something, then they cannot react to it in the first place! The characters react to what they perceive and know, and the GM should be telling them what that is.
Obviously the DM should tell the player what the character is perceiving
"Through the door you see a room full of dust, some broken furniture, and old dry spider webs"
"You cast your spell but it does nothing"
"As you enter the room you realize it's a highly unpleasant place to be, make a Wisdom save in order to not immediately turn around and leave"
but the DM is under no obligation to tell the player anything the character cannot perceive or has not yet perceived
<the room is under the effect of a Vacancy* spell, what you see is an illusion covering what's really there>
<the caster has been unknowingly hit by a magic-denial effect and cannot access magic right now>
<the room is enchanted to have a repellent effect on any non-Evil creature that enters>
Seems to me it's the latter piece some (not including me!) are disagreeing with; suggesting instead the player should always be told this background info even if the character doesn't know it.
* - an old 1e Illusionist spell, not sure if it lasted into later editions.








