I feel like you aren't really grasping what I mean by "Say yes" and how it relates to asking things of the GM versus asking things of the rules.With the caveat that all this assumes both interpretations of the hypothetical are implemented:
I only mentioned NPCs (which includes monsters) because that seems to be the place that GMs would retain the greatest authorial control in the world.
Not at all, I'm just drawing a line between "game" and "play" (after all, there are improv games). But on the scale of "miniatures wargame" to "improvisational theater," accepting both versions of the hypothetical puts you very, very close to the latter rather quickly.
Ah, like an enemy who has a specific weakness you must figure out how to exploit in order to defeat it! Or a door that only opens if you push on it the right way! More seriously, though, the trouble I would run into here is how the GM would tell the players they failed (or present any puzzle with a predetermined solution) if they aren't allowed to say no.
It seems to me the most likely thing that will happen if you come across a door you don't know how to open will be the question: "I try [x]: does that open the door?" To which the only answer is, of course: "Yes." Alternately, I suppose, you'd could be equally likely to have the rogue say "I look for a way to open the door." They roll to Find Traps/Open Locks and, of course, they succeed.
If we're not bypassing the game rules, it should be easy for you to choose two or three specific game rules from any system which wouldn't be effectively ignored by both assuming all chances of failure are nonexistent and always saying yes to player suggestions.
But the roll will always be a success, so we can't do that, and the players can also make up whatever they want. The hypothetical is exactly what is removing those options.
We are explicitly not talking about auto-success (anymore; that was a relatively quick realization in this relatively long discussion). If the answer comes from the GM ("can I play a half orc half unicorn?" "can I find a prybar in the pantry?" "can I have a connection to the royal courtier?") the answer is always "Yes." If the the answer comes from the rules ("can I hit the ogre with my bow?" "can I jump across this chasm?") then the dice do whatever their job is. Different systems have different capacities for these two things, ranging in broad categories including fighting, talking, exploring and so on. For example, 5E gives the GM a lot of latitude in determining whether a roll should be made in many instances, so I say that in 5E this method would result in a lot (but not all) "automatic successes" outside of combat that another game, like Rolemaster or Pathfinder, might not.