Ummm
Ummm

Ummm

I ask this, or for their stealth modifiers, and then roll behind the screen just to fuck with them sometimes. But it's actually quite useful. I do this once in a while and it trains them not to overreact (and assume ambush) when I ask them for realzies.
On player training, I like systems where you can bribe players to let bad things happen.
Like in vampire: the requiem, a player can always turn a regular failure into a Dramatic Failure, and get a little XP. This meant the players went from "oh no the cave is probably full of monsters let's take forever stressing" to "I ROLLED GARBAGE CAN I JUST BARGE IN LIKE A CONFIDENT IDIOT FOR MY DRAMATIC FAILURE?"
Tastes vary, but I found it made a more interesting and snappier game.
Like the Fate system!
I like systems that are player-driven, like Dungeon World. Instead of me putting a bunch of traps into place and hoping you walk into them, the complication of you rolling a failure on something else might mean there's a trap there.
"Are there any traps there?" "You tell me."
I made it a routine to ask perception and stealth modifier of every player at the beginning of each session m
Remember, total darkness is -5 to passive perception even if you have darkvision.
Then what is even the point?
Because without darkvision you automatically fail (and get hit by advantage/disadvantage for unseen attacker/target).
I'm casting fireball