Julien: (laughs)
GON: Is that something that you find people doing? I expected the clues to be a bit more vague. Did you find this doing playtesting? Did you put it in because people didn’t know what to do?
Julien: Yeah. We try not to lead the player by the nose, but at some point we found that if we don’t give a little information, people just get lost and don’t know what to do. It’s just overwhelming. So we tried to add this element that gave just a hint, to help a little. But we try to do it as little as possible.
GON: It’s cool because there’s a lot of ways up the stairs, but it still felt a bit railroad-ey. What did people do before you put these clues in?
Julien: People would just walk around. They didn’t know what to do. They didn’t even go upstairs because a guard told them they couldn’t. They’d say “Okay, I can’t go upstairs.” They wouldn’t do anything.
http://games.on.net/2012/09/dishonored-interview-arkane-on-stealth-ai-player-choice-and-much-more/
Seriously Arkane, you should just let them find the way, they will manage somehow. Do not make the game easier because of Play Testers please...