What my players hear depends entirely on how well they roll. Nat 20? What do you know, the orcs just happen to be going over their plans. Nat 1? The orcs hear you. A passing roll, but just barely? You overhear one of them fart and 2 others laughing hysterically.
This is a situation with an element of luck and you’re literally using luck to determine if they even succeed; why not incorporate the numbers in the roll to reflect the random nature of the game world’s reality?
Fail but barely? You hear one of them say he needs to use the chamber pot and head towards the door.
Por que no los dos?
“But how were you able to make the casserole? Weren’t you busy with the boss’ plan?”
“Nah, let me go over the details of the plan and explain how I managed to fit casserole prep into my schedule.”