I think if they genuinely don't know that you fudge then, yes, it won't affect how they think and their feeling of challenge.
But it is still 100% true that THE REASON that you are fudging is 100% prioritizing in-game drama over something else. You openly stated that you were trying to go against "extreme bad luck"--a possibility all players could have included in their calcuclations, and one included in the game design.
In other words: you fudged in order to disallow a possibility the rules allow and the stated reason to disallow it was to create a situation where death from what your story considers a "minor" encounter is less likely than death from what your story considers a "major" encounter.
No, that's not 100% the case. It's a lot of the time, but it's also often a question as to what's 'fair' or at least seems fair. One way of looking at what's fair is noted in the 1st edition DMG - that is, let the freakish roll stand, because the players will have freakish rolls from time-to-time as well.
But another way of looking at whether that is fair or not is the fact that the players will have far more attack rolls made against them, then they will against any given creature. That is, if going by strict statistics, the players should always die eventually during the course of the game. Is that fair?
Well, in a strict numbers game, sure. But in a heroic rpg, maybe not. Or more accurately, maybe not for every game. My last campaign ran with the same core characters for 8+ years. A current one has been running for over a year. The players have a lot of investment in these characters, and the campaign is built around the characters to a large degree as well. These are the heroic characters, not necessarily known on a global level, but certainly a local, and sometimes regional level, that have beaten the odds and survived. Strict statistics doesn't support that.
When we could play for hours a day, multiple days a week, then some characters naturally survived to legendary status, and many others didn't. But now we're once a week for about 3 hours a week, statistics aren't our friend. At least not for the sort of epic story that ties these specific characters closely together.
There's another poll/thread about fail forward and what that entails. The 1st Ed DMG comment on "maybe they lose a limb, or fall unconscious instead" and other options instead of death feels an awful lot like 'fail forward' and some people find that very objectionable. Is that approach better or worse than just fudging the roll? It depends on the person I'd guess.
I was not the one that discussed the minor over major encounter. That's not typically a concern of mine. My main concern if I do fudge is that the result works for the story, combined with the 'freakish die roll' that would inappropriately affect that story. Hey, if the PCs are going to die because they are stupid (like the bard that decided she was going to jump into a seemingly bottomless shaft to the underdark), that's fine with me. I'll usually make sure they understand what I'm describing before that. And give the other PCs an opportunity to stop her. But if she dies, she dies. That's their own stupidity. But if it's a bad die roll, or sequence of die rolls, that might make a difference.
Others state that challenge-oriented players are naturally against fudging. I'd also question that. If they don't know fudging is happening, how would that alter their perception? I certainly don't think it's impossible to have a challenging game while allowing fudging, even if you learn about it afterwards. Some people obviously place a greater emphasis on succeeding because/despite the die rolls (beating the odds, essentially), which I guess puts more emphasis on that over the story. But even if given a bit of help from the Gods (DM fudging), they still beat the odds. They just were weighted a little bit in their favor.
But the reality is that not fudging is also disallowing a possibility the rules allow, which is, well, fudging.
If fudging is against the rules, that's one thing. But it's not. Explicitly so. They are mutually exclusive options, but both are acceptable by the rules as written. It is not called out in a sidebar as a variant rule, it is in the main text as an acceptable, and core rule.
So since they are both allowed by the rules, then the question becomes who gets to make that decision?
Here the rules lean very heavily toward the DM. Repeatedly throughout the core books, in questions regarding variant rules (which this is not), players are told to 'ask their DM.' The DM guide specifically names the DM as the master of their world, whether based on a published world or otherwise, a master of adventures, and a master of rules. That is, the DM decides what rules are in play in their game.
So based on the rules as written, it would appear that:
The DM decides what rules are in play, and that fudging is an acceptable and core rule, as is not fudging. That doesn't exclude other alternatives, but it is RAW. The DM doesn't even necessarily need to declare a preference. Fudging is one of the many tools (along with dice) that the DM has at their disposal. And at a given point in time, fudging might be the tool they feel is most appropriate. And RAW - that's fine. No apology or explanation required.
Does that mean that a DM shouldn't take into account the players' preferences? Of course not. There is a page entitled "Know your players" that talks about different play styles. Note that it describes play styles, but does not prescribe any specific rules based on play style. It doesn't tell you that DM's should include specific variant rules, nor does it specify which rules are appropriate when one or more rules are conflicting (in the case of to fudge/not to fudge).
But we're playing with people, and people's preferences, even down to a rule level, need to be addressed if there's an issue. It might not always go in a specific player's favor, but it should at least be addressed. I'm an 'intent' of the rule guy. To me, the intent of fudging, whether narrowly defined as modifying a die roll on the fly, vs modifying monster stats, adding removing monsters, etc., the intent of the rule allowing fudging is to ensure that the DM is in control of the game, and not the dice. The dice are tools, and the vast majority of the time are the right tool at the time, and should not be changed. But every once in a while, they aren't. And for those that would argue this point, 5th Ed DMG, pg 237:
"Remember that dice don't run your game-you do. Dice are like rules. They're tools to help keep the action moving. At any time you, can decide that a player's action is automatically successful. you can also grant the player advantage on any ability check, reducing the chance of a bad die roll for foiling the character's plans."
At any time includes following a die roll.
As I've said, I'm finding the discussion interesting because I'm always looking for ways to improve as a DM. If nothing else, it forces me to try to answer why I do things the way I do, and that's not always an easy answer as well. I'm am interested in what my players think if we were to start rolling everything out in the open, and what happens, happens. Personally I don't think they'll like it. I also don't think it's crossed their mind. All of my groups have seemed to view the job of the DM as a writer and a referee. A part of the job of the referee is to adjudicate, whether it's a written rule or a die roll. So they've never seemed to care. They just like the game, like the story, and it's sort of "whatever it is you're doing we like, so keep doing what you're doing."
Ilbranteloth