Slight change for conversations?

[pango]

What I always found interesting as a teenager was how they would never mark a location on your map if you were asking from inside a building

I assumed it's not a technical reason, but purely gameplay mechanics: it gives you some incentive to arrive in towns during the day so you can get more help finding directions.
Maybe that could have been achieved differently, say if you arrive too late at night the only guy on the bridge is the bartender, and if he doesn't know directions, well you can either explore the town on your own or rent a room for the night and sleep...