“To Cast the Die, Yet Declare Only That Which is Most Desirable”
Why would a Gamemaster ever “fudge” a die roll? That is, to declare to the players that the result of the roll was other than what actually came up? If you have ever Gm’d a game, I’m sure you either have done this or at least thought about it.
This has nothing to do with the players changing their roll… that’s just plain cheating and shouldn’t happen at your table. I’ve had players who think they’re sneaky enough to pull this off, but it’s been pretty obvious every time. One player in particular cheated on almost every roll. The whole table knew he was doing it, and it was so obvious and ridiculous that we silently just let it happen. I compensated for it in other ways.
My personal rule about when and why to fudge a die roll is that I’ll never do it to benefit monsters. It’s always for the story. If the die roll has the potential to derail the story, or if it could result in a very un-heroic death of a PC, I’m likely to change it. That doesn’t mean I won’t let characters die… I just don’t want the death to be unsatisfying.
Never fudge a die roll just because your players have managed to wipe out a favorite monster in record time. Don’t fudge a die roll to “teach them a lesson”. Don’t do it for a power trip. Use it to keep the game flowing, fun, and exciting. It’s not a matter of you vs. them. If it is for you, stop it.
Here’s a great example of when I should have fudged a die roll but didn’t and regretted it later: my group of players had managed to board and steal a small frigate, and decided to try their hand at piracy. Unfortunately, their decided route took them near an island that was home to a very large number of Drow that had found a path from the Underdark to the island an were in the process of building a fortress from which to build and launch SpellJamming ships of their own (This was a 2E/3.5 game). One die roll came up that would have let the players escape in their ship without being spotted. I really wanted the encounter to happen, so I decided that Yes, the players ship was spotted and the Drow would send out a boarding force.
Very bad idea. The player characters were REALLY not up to dealing with a large number of Drow, even with the dark elves disadvantages in the bright sunlight. This encounter resulted in a TPK (total party kill) and a miserable group of players who thought (rightfully) that I had hit them with way too much. All just because I fudged a roll.
I learned my lesson. I don’t ever fudge rolls against the players. I will use my power to advance the plot, and to increase the dramatic flavor of an encounter.
If you’re ever not sure whether changing the result of a roll is a good thing or not, just look at your players, and consider the story. Will this make it more fun for all? Then go ahead. Could it ruin the scenario or the whole adventure? Don’t do it. Will it kill a PC in a boring way. Absolutey not.
Whatever you decide, it’s up to you. I wish you luck with those decisions, and with your game!