Perhaps I run a different game from DMs people have played with in the past. It seems I've been confusing players recently and I need to clarify some things; namely, the function of NPCs in the game and what PCs can expect when dealing with them.
It's kind of a classic trope in RPGs that there's something like an old man standing on a bridge just waiting to give the party information. Let it be known now that this is as far from the type of character that will be encountered in my campaign as it's going to get. I would like to clear up once and for all any suspicion that as the DM I am 'communicating with players' through NPCs. I am not. I am portraying NPCs as I conceive of them, as people with ambitions, fears, acne and dandruff, who laugh when they're tickled, wake up with morning wood, enjoy the scent of dog feces, and so on. They are not automatons simply placed there to give the party convenient hints.
As the DM in my campaign I have been inaccurately referred to as 'God'. No. The dice, and the random numbers generated by the Excel spreadsheets, are God. I am simply the world. The world, like John Shaft, is complicated.
The first thing a wise player will do is to stop taking everything NPCs say at face value. This is not to say that most NPCs are dishonest, but as people they have their own agendas and such should be taken into account. Maybe that peasant that you questioned was too proud to say he didn't know, so he made something up. Maybe the constables are testing you with information because they think you might be enemy agents. Maybe the old woman who told you everything she knows was telling you anything she could think of because she was lonely and wanted you to stay longer for tea. You won't know until you act in some way in regard to the leads you've been given, and maybe not even then.
If someone wants you dead, and that someone is smart, it's not going to look deliberate. In some places, of course, NPCs will be a basically friendly and charitable lot; but other places are a hotbed of intrigue, and PCs will have nothing but each other to keep them alive. Part of developing your skill as a player is being able to tell with some degree of accuracy which of those you might be in at the moment.
What the DM will not do is make it easy for you.