Scenario: You're playing an 18th level character you've run since first level for over 3 years in real time. He's the leader of the party, and the hope of middle-earth. He's defeated dragons and hordes of undead. His magic weapons are legendary. This character is really part of YOU. You've played with him every week for THREE years.
Your party is on their way to the island fortress of the Demon King for the final epic battle. It's gonna be awesome. The entire campaign has led up to this. You have to swim across a river to reach the castle. You roll a 1 on your swim check. You get another chance, and roll a 2. One more chance, roll another 1. You are swept away and drown. Your character is dead. You miss the final epic battle, because you had a bad stroke of luck, and the greatest hero the world has ever seen drowned in rather unheroic fashion.
You're totally fine with that?
I'm playing a game. If the dice come up, "You failed three skill checks," then that's what happens.
Yes, I'm totally fine with that. That's specifically why I opted to play a game as opposed to writing a story or some other like activity where I get to choose my character's fate.
I also don't play roleplaying games with the expectation that the end result is supposed to be an epic story. I approach gaming with the attitude that what happens in play
is the character's story, and while my characters pursue goals and build relationships, I don't presume that they are destined for greatness or some special purpose. My characters succeed or fail because they succeed or fail, not because of some out-of-game presumption of ultimate success or timely, 'appropriate' failure.
And my characters are never, ever part of ME. I'm excited when they succeed, and bummed when they fail; I'll work my tail off making an effective character and playing him as sharply as I can, and when he's swept away by a river, I'll bewail the cruel hand of Fate. But it's still just a character in a game, not ME.
I'm all for letting the dice land where the may, and I will absolutely NOT protect a player from a combat death, but I just don't think a great character dies in a trivial manner.
I don't think the death you outlined above is in any way "trivial."
The adventurer is swept away by a dangerous river crossing, leaving the rest of the party short-handed as they prepare to face the BBEG. That's actually pretty epic on the face of it. Do they press on, or do they fall back? That death creates an interesting dilemma.
And I assume it must've been a dangerous river crossing, and that there was a compelling need to cross it, because if it wasn't dangerous and necessary, we could've found a safer way to cross, like flying a character with a rope across the river and rigging a safety line, and that the referee wouldn't put a "trivial" challenge in front of us if the referee didn't want death to be a possible outcome facing the adventurers.
One of the great failings I see in situations where gamers advocate fudging is creating what are meant to be 'color' situations and forgetting that if the dice are involved, then unexpected outcomes are possible. In my experience most instances of fudging arise from something along the lines of, "Oh crap, I didn't think that would happen!" It reflects poor encounter design.
The basic rule of thumb is, don't roll the dice if you aren't prepared to accept the results, and if you don't want death or another serious consequence to arise from an encounter, then don't create an encounter where death is possible due to bad luck.