I think it's a lot different - the bad rolls for the players and/or the good rolls for the DM still stand, it's just that they get some in-game help. It's like bringing in a relief pitcher in a baseball game.
By the way, while I often have that 'unplanned' ally in reserve, I've only had to use the unplanned ally like that once in 4 1/2 years.
Also, I make all combat rolls (to hit, damage, saving throws) out in the open. Things like NPC reactions and opposed rolls, I do behind the screen because the PCs don't need to see what their bonus is.
You can
think it's a lot different. But it
isn't in any way other than aesthetically.
You made up a character and put that character someplace they weren't and only revealed the existence of that character when it was necessary to save the party - but pretended that character didn't exist if it wasn't necessary.
Hell, if anything, you've potentially de-protagonized your PCs
and fudged
at the same time.
The moment you've had that NPC conveniently show up, you've fudged. The moment you have the monster conveniently change targets to the NPC (or even another PC), you've fudged. The moment you have that NPC conveniently armed with some kind of healing magic (or conveniently have some healing magic in the monster's treasure), you've fudged.
I don't think this fudging is a bad thing, mind you. But that's because I acknowledge that a GM is not a computer running an infinitely-detailed simulation tracking exactly where each NPC in the universe
actually is and exactly what's the likelihood of said NPC being equipped the way that s/he is and exactly what the "aggro rating" (to borrow from WoW) a given monster has for each combatant in the field. Just like I don't assume the GM is perfectly cognizant of or even interested in every possible outcome when s/he picks up the dice.
This fudging is what the GM must do to be a GM, of course, every time s/he makes a decision - about the existence of an NPC, about what said NPC knows and can or will do, about the power level of the monsters in this particular dungeon or room.
And sometimes the GM
unwittingly fudges simply as a result of options s/he didn't think about or realize. Seriously, the number of times I've had monsters fight to the bitter end when I
should have had them run or forgot about the NPC that was with the party but wasn't attacking this whole time or choices that I was tactically ignorant of... The list goes on.
But just because you're dressing it up better doesn't make your fudging any less extant.
Or, as Mark points out, better we call it adjudication - because that's what's being done.
Good list.
When I DM and I notice that this kind of situation is occurring, my normal technique is to modify the behaviour of the creature rather than its stats - maybe it attempts to flee rather than fight to the bitter end against badly wounded foes, maybe the intelligent creatures decide to capture for info or ransom rather than TPK the adventurers, and so on.
But, again, modifying behavior
is just another form of fudging.
If you or the writer of the monster description initially wrote that creature as "fighting to the bitter end", you're arbitrarily changing those preset behaviors because having it wipe the PCs is no fun. You've fudged. Even if that "preset" wasn't there, you're fudging when you arbitrarily make that decision based on what's
convenient (for the PCs, for the story, for the fun,
whatever) rather than what is the most brutally efficient.
But you're not a bad GM for that. In fact, you're probably a good GM, since you're attempting to maximize everyone's fun but not TPKing the party because of a bad choice on your part or a run of bad luck on theirs.
But, yet again,
you're still fudging.