hawkeyefan
Legend
It seems a lot more likely than you suggest. Maxperson’s example involved the Csptain of the guard, who is more likely to be a major NPC than a minor NPC.
If the players want to burn an orphanage, there is probably an in-game reason for it (heck, if there is an orphanage in the adventure, there is probably an in-game reason for it). Stands to reason that the DM would have q pretty good idea about how most NPCs (both major and minor) feel about the orphanage.
Okay, I'm going to approach this from another angle.
Who has determined that there is an orphanage of some importance? The DM.
Who has determined there's a NPC who has very strong feelings about the orphanage? The DM.
Who has placed this NPC in the path of the PCs? The DM.
Now......if the DM is fine with how things play out as a result of whatever interaction the PCs have with this orphanage-loving NPC, then I suppose the above facts are not a problem. But if it leads to a dissatisfying encounter or interaction, then I think the DM has to be held at least partly accountable, right?
So to lend the example a little more weight....because the whole orphanage burning thing is pretty absurd and it's hard to even use it as an example......let's say that the PCs have reason to believe that the headmaster (?) at the orphanage is in fact a cultist, and he's replaced all the orphans with shapechanging imps from the lower planes. This is something the DM has in his notes. The PCs have become aware of this plot, and are devoted to stopping it. The captain of the guard will likely frown on the PCs trying to burn down the orphanage.....we don't even need to add details like "oh he was an orphan himself, so he's sympathetic" because almost no one wants to see an orphanage burn down.
The PCs are concerned they can't foil the cultist's plan.....so they decide to try and convince the captain of the truth and to ask for his help.
Now we have a situation that has come from the DM's notes and has played out largely as hoped/expected. But will the captain be convinced? This seems to be the dynamic point.....what will happen?
DM SAYS NO!
Not allowing the PCs to convince the captain no matter what would be a bad decision in this case. What if the PCs show him an orphan and they then dispel its shapechanging ability, revealing its true form as an imp. Still not believing? What if we show him the cultist's journal, swiped from his nightstand when the party rogue scouted the place out....the journal clearly details the cultist's plan. No? Still not convinced? Man you love orphanages even to a fault.
You're shooting down their plan before they even have a chance to see if it will work. There are several points where the DM could make a different choice that totally shifts how this may play out.