The thing with that example (FF7) is that you also have a non-world marker already telling you you can climb the cliff.In fact, I'm going to say it, the best markers and so on are, indeed, those that just sign you that there's a thing there in a non-world way.
As in, a literal translucent arrow pointing towards a place, to put an example, there's: >>32633
. That's a non world sign, it's clearly obvious that that sign isn't there on the world of the game, but put there by the devs in order to communicate with the player, if you have problems with such non-world communication, the HUD in of itself is also a non-world communicator, like the minimap is as well; text-boxes are also non-world communicators, in reality there shouldn't be any text-boxes (or subtitles) and you would only listen and attend whatever the NPC is telling you verbally in their own language (english, japanese, spanish…); your HP and MP are also non-world communicators, people don't say "I'm low on health points, -5 points and I'm dead", they might say "I'm feeling weak right now" but that isn't a direct reference to the HP, how many HP points do YOU
have right now?
You don't know, and the character you're playing doesn't know either. Do objects that matter to you/MC shine brightly like a lightbulb? No, and in that world they do not as well, but the devs let that object shine in order for you to get it. It isn't part of the world.
Non-world communicators are communicators that display only for the player and not for the characters of the game, and thus are probably the best non-world communicators, easy to understand, and completely realistic because the player inherently knows that that sign isn't in the world itself, but a non-world communicator left by the devs to make the players life easier.
This is, in part, the problem I have with the games that apply the yellow (or any colour) treatment to important objects. In games like Mirror's Edge they're important because the game is, exactly, about going fast as fuck. The game's plot doesn't matter, gameplay does, and it benefits a lot thanks to the treatment of the red paint which also contributes to the art department of the game, in games like Uncharted, which try to go for maximum realism, I can somewhat understand it, and the devs also try to hide the fact they're using yellow, but in FF7 you have the yellow paint in a cliff, which also has a non-world marker, in a game which is really fucking blunt about where you have to go, and this cliff looks like it's on a habitated place, on the moment they're going to the lab and shit during the flashback. Are you telling me that the goverment has set up a lab in order to make weird mutants and shit in secrecy, and the scientist, in order to get there, have to go through a cliff everyday, so much that they have actually painted yellow the cliff? Or better yet, the scientist live in the lab, and thus they have actually gave away their location by unsubtlelly painting the parts of the cliff necessary to reach it? Wouldn't have it been better to just get some string ladder there that you can withdraw so people don't go climbing the cliff towards your secret lab (wasn't the lab also the energy plant of the town?)
Once you implement a "subtle" in-world communicator, such as the yellow paint, in an absolutely lazy and brute way, people start to ask questions about why is that in the world. If the answer isn't found in the game, then it takes the person out of the experience. Meanwhile, non-world communicators don't take the player out of the world because it's honest, it's just a help from the dev.
That's about it. In-world communicators depend on lying to the player meanwhile non-world communicators do not, and of course, if in-world communicators actually work if it is actually able to convince the player that it's part of the scenery and not put there by the developers. When it doesn't work because there's no actual reason for that to be painted yellow, the player will feel either cheated because the devs think they can deceive him and thus the devs think he's a fucking imbecile, or amused because the devs ridiculed themselves in their puny attempt at trickery.It's all about the devs being honest or not, really.