In a game where the DM decides everything about an encounter, how tough the enemies are, what abilities they have, how many HP, how many there are of them etc, I kind of don't see "fairness" as a factor. To me it can be a bit like saying that spaghetti is "unfair", I can't even see the context of how fairness is relevant to the object in point.
I have recently started to understand that position though. After playing a bit of the old Space Crusade and Hero Quest games, I can see how a dungeon crawl can be challenge to be overcome. One guy designs it as best they can and you go hammer and tongs to beat it. That can be fun too. It takes a well designed dungeon though, or you spend a couple of hours doing something very boring if it is too hard or too easy.
I suspect that however you start playing the game, will dictate your point of view on this and I suspect it is rather hard to change. I can fully see that if I started playing under a certain style of DM, using a certain system, or had previous experiences with other "fair" games, my points of reference would be vastly different and I would feel strongly against fudging.
I could not even tell you if I am fudging half the time as a DM. That kind of implies that I have some sort of stone carved commandment that has to be obeyed. I tend to wing things a lot more than that. I am not even sure where the line is. Don't get me wrong, I'd be a better DM with more preparation, but my players literally turn up at my house for a game without telling me quiet often.
I know that the PCs have burst into a guard room and will fight 8 guards, if the fight looks easy and I add in two more guards coming into the room, is that fudging? What if I had not decided who was in the next room yet? What if I had and changed my mind? How do I know when I am "cheating"?
The PCs are fighting a Wizard, in my head he is "pretty powerful" but I have not picked out spells for him in advance. If he pulls out a feather fall when kicked out a window, is that fudging? If I am using an adventure module and and the designer did not give him a spell, but I use it, am I bad? Is it the adventure designer that decides if I am fudging? Do I enter into a contract to run the book the way it was written?
In most cases, I have no written stats for NPCs, if I decide on a to-hit bonus for them on the spot, is that OK? Is it somehow only authoritative if I had written it down in a notebook before hand? What if I change the notebook? At what point have I breached a contract with my players?
If I design a tough fight with a Barbarian lord and the HP total I had in mind does not make it a tough fight, can I change it to be accurate to the description, narrative and in-world consistency or do I abide by a mathematical mistake? What if I had not put an exact number down before hand? I'm just not sure at what point I am fudging, is it when I decided to use a character not in the Monster Manual? Is it when I wrote it down on a notepad and didn't stick to it? Was it the act of writing it down the made it authoritative?
How do fudge-free PCs and DMs feel about creatures having abilities that are not in the rules? As a couple of examples:
- PCs came across a monk who did a death-touch attack. He hits you, con save or fail a death save. No damage done, you are still fine, but one death save is down. Don't let him hit you three times.
- PCs came up against Lord Soth and found he simply could not be killed at all, he would never drop below 1HP. They had to unravel the curse that bound him to his domain to have a hope of defeating him.
- In one campaign, PCs came across people who had certain fates that they could fortell e.g. Will die by drowning in sea water. They could not hope to defeat that particular enemy without some sea water. Every attack that would have dropped them below 1HP auto-missed regardless of the roll.
- A swordmaster who never misses. If he would have missed every attack on his turn, he instead did a dodge maneuver, or was feinting, giving him advantage next time.
I guess I am just curious if the concept of fairness comes into encounter and power designs, or just the playing out of the encounters once designed, regardless of their construction?
All in all, I am actually really inspired to run an old-school style game, like Ravenloft or Tomb of Horrors and just play it completely without fudging. See how many PCs it takes to finish the adventure module.