In other words, in Banana's interpretation stealth isn't actually possible. Not only is stealth not possible, but something that is practically automatic in the real world..."hiding" when you can't actually be seen...requires you to roll your Stealth skill.
That's a remarkably disingenuous reading of my interpretation.
"Ok, I'll Hide behind the stone wall."
"Huh? It's 8 feet high. I stand behind it."
"Yeah, but now you need to roll your Stealth skill."
"Crap...I rolled a 4."
"Ok, you're standing back there and you sneeze."
"You said there's a thunderstorm..."
"You sneezed really loud."
My ruling merely asserts that there is a difference between "cannot see you clearly" and "doesn't know you are there," and that the Stealth skill is for moving from the former to the latter. The assumption is that even if you can't see something clearly, you know where it is, because humans are not purely visual creatures and for the purposes of abstraction it's assumed that PC's and NPC's are paying close attention to their surroundings.
Yes, running around the corner of a wall by itself isn't enough to make an enemy lose track of you. They can't see you - you have
total cover. But it's not like you've stopped breathing heavily from carrying 100+ lbs of equipment or like your armor isn't making metallic clanks or like they didn't hear where your footfalls stopped. They know enough to know if you'd be caught in a
fireball placed at the edge of the wall.
If you run around the corner of the wall and use the Hide action, though, that Stealth check is you quieting your breathing, trying to smooth out your armor's movement, and picking the right terrain to put your feet. If your Stealth check is successful, they don't know where you went (just that you disappeared around the side of the wall), and so they won't know if the
fireball placed at the edge of the wall would catch you or not.
So yeah, running around the corner of a wall and then "sneezing loudly" (or stepping on a branch or stumbling and making an involuntary cry, or not being able to quiet your breathing, or whatever makes sense in context) is a thing that might happen if you flub a Stealth check.
It's even supported in the PHB:
...if you make noise (such as shouting a warning or knocking over a vase), you give away your position...Signs of [an Invisible creature's] passage might still be noticed, however, and it still has to stay quiet...In combat, most creatures stay alert for signs of danger all around, so if you come out of hiding and approach a creature, it usually sees you.
"Knocking over a vase" and "sneezing loudly" seem to fall into the same general camp of "failed a Stealth check and gave away your position."
Uller said:
As always...reading some of these stealth threads, it's like some folks never played hide n' seek as a kid or never snuck up on someone to startle them as a prank. Being stealthy isn't hard.
You're under-selling how hard it is to be sneaky (it's like ET was hiding from someone who was familiar with aliens like him and in fact has occasionally been in fights with them in a dangerous world of high adventure) but even if you weren't, there's other reasons to prevent Stealth from being an "I Win" button.
Like, this isn't the
Arkham games where if Batman sits around for 30 seconds everyone just forgets he was ever there and for some reason nobody uses flashlights. This also isn't something like WoW where you just go invisible when you enter "stealth mode." In the story of the sneaky rogue, they must use the environment and their context to their advantage, choosing the right time and the right place and the right kind of distraction and every act is risky.
Stealth - like anything else - should be an Interesting Decision, not a common and universally available default tactic.