I was talking to a GM buddy of mine, him and I are alike inasmuch as neither of us are very good at playing a TT RPG. We both kinda suck at it, being too "get to the punchline, get it done" oriented. But, we do great at running them--albeit in very different ways.
He, we'll call him Agnew, is a much more "miniatures and grids", "by the book", "I won't deign to run that which is a lowly system in mine eyes" kind of guy; I'm a more "don't get hung up on the rules", "cinematic is the science" kind of guy. Needless to say, that's meant that we have different "go to" games for each of us. He starts with the system and works his way through planning to get to story, and I start with a story and leave it to the players to pick what system they feel in the mood for in a given night (I'm possibly a bit jaded, having run games almost exclusively for years and years, rarely in love with anything and finding almost everything to be as good as anything else).
So Agnew and I are chatting it up and we get to the issue of GM fiat--whether or not its legitimate or a good idea (two very seperate issues) to change stuff on the fly or use metagame knowledge to influence the game.
The thought-experiment we cooked up to explore the space was you have a group of players, they are very up close-combatty types. Not by design, but circumstance, they don't have or do much in the way of ranged hoodoo. Now, you have a part of the story where you want them to face down a dragon (we had to settle on a genre for story, because it was hard to discuss outside of that framework). Given that they're really good at close-combatty stuff, and given that you had planned on a nice cave with minimal space for running around--is it a legitimate move to reinvent the encounter on the fly such that the cave has a really high ceiling and lots of space and the dragon just happens to like flying around and occasionally dive bombing the shit out of adventurers.
Would it be acceptable to alter the game's storyline to include that, because of knowledge out-of-game about how the players fight?
And further, what if it were a more gross violation--one not so easily played off by saying "oh, it was feasible to do this new thing regardless"? Something like giving your supervillain boss some kinda mind-burning-psychic-mojo powers, given that the players are quite tanklike and their mental hoodoo is their weakest point?
Or similarly, in the other direction, changing their fights so that they are more likely to win--maybe the dragon never uses its breath weapon... or the supervillain makes (gasp) a fatal error in the fight?
Agnew felt that it would be an almost unforgivable sin to make such changes--he's of the mind that the world was designed a particular way, the encounters a particular way, and its an unfairness to simply cater to or cater away from player success.
I more or less disagreed, taking a very "very little is sacrosanct" stance about what could or couldn't be altered in the name of making a "wicked cool" story happen
Thoughts?