
Darksol the Painbringer |

(This is going to come off as more of a "rant" post, so if you're confused as to what I'm asking for, don't worry about it.)
So, one of our sessions resulted in our Good-aligned PCs being too trusting and inquisitive of a bad guy who is clearly insane, as well as a serial killer (and not even living, I might add), almost caused another PC death. (It's my PC, actually, and the only reason I'm not dead is because the GM pulled some punches, though I was perfectly fine with dying and making a new character with the most defenses/immunities possible due to all of the Save/Die effects we keep dealing with.)
Because we talked with him in an attempt to get useless information, we bought him time to basically hulk out and beat the crap out of us (well, mostly me, but he had minions attacking us too), and brought out even more and tougher bad guys for us to fight. Needless to say, the fight became a lot harder because of players being Stupid Good, and we just barely came out without permanent loss.
I even pointed out to them that A. The guy isn't even alive (he's undead), and B. The guy is known to kill people without mercy or even reason. There was no point in reasoning with him or trying to interrogate him (especially when we found our next plot hook before facing him), meaning talking with him would've been pointless.
However, they apparently still valued the idea of restraining and talking to the bad guy, even though they were notoriously evil, and evidenced by how badly we were beaten up, a dangerous threat that was best not left up to some words and a pair of manacles.
Now, I will say that we were lucky (and that the GM wasn't up to killing another PC after we had another one happen not too long ago), but how long will that luck (or GM forgiveness) last until we get a TPK? I'd rather not find out, which is why I made this thread to get advice about what I should do if I come into another similar situation.
Should I just go against the group's decision to talk and just eliminate the threats entirely? Are there some other arguments I can use to convince fellow players that being trusting or forgiving of a BBEG is not a good decision? Or am I just going to have to accept that my fellow players are going to get us into a TPK because they think an undead murderer is going to talk or drop his weapons in defeat?

Rub-Eta |
If you share this point of view with your character, you can probably solve this in-game. Even if you can't talk them out of doing these things, your character will probably start taking precautions from getting to deeply drawn in to the other characters' actions: It's perfectly reasonable to role-play "I don't think this is a good idea, but you guys go in, if you want to. I'll stay outside and keep watch".
Again, not being a dick about it. Just make it clear that your character is not suicidal.
This way you avoid a TPK.

Jarrahkin |
You trying to reason with them is about as pointless as the party trying to reason with the bad guy.
If you're convinced that the bad guy needs killing, initiate combat yourself...once you open fire, everyone is committed and they'll be forced to back your play.
You'll likely have arguments about it afterwards, but as long as it's kept in character it should be manageable. Much better than having the TPK blame argument (which can't be done in character).

PossibleCabbage |

I feel like this is a thing where the players and GM need to come to an agreement about whether "my character is naïve" is a character quirk or a tactical error. Both are valid perspectives, but it's important that everybody agrees on which perspective the shared narrative takes.
Since on one hand, a GM wants to reward a player for thoughtful gameplay, but on the other hand a player does not want to feel punished for roleplaying a flawed individual.
So we've got to figure out whether this is a deliberate choice, and everybody just happens by chance to be playing gullible rubes (which is valid!) or if it's just this is just the players not thinking things through the way their characters ought. I generally find in practice that if the tone of the game is not appropriate for the naïve player to survive through happy accidents, then the rest of the party is responsible for making up for that character's dearth of cynicism. If a player, in character, suggests a bad idea the party is under no obligation to go along with it, after all.

Darksol the Painbringer |

Well, before giving out any advice, I have some questions. First off, what class is said Good character, and what deity do they worship, if any?
For the record, I did mention PCs, plural. Not just a single PC.
First is an Aasimar Paladin (doesn't worship a deity because GM doesn't require it). This is actually the PC that initially died, and when we revived him, he was "crippled" a little bit (GM basically nullified all of our treasure up to this point and brought him back with 4 Con Drain instead of 2 Levels) for this fight. The irony here is that he's the one who initiated the interrogation which caused the BBEG to hulk out.
Two other characters are a (modified) Wyvaran Warpriest and a Half-Elf Inquisitor (both of whom are Lawful Good). Both characters are worshippers of Ragathiel and use Bastard Swords as their weapons. Last I checked, Ragathiel isn't above the whole "Redemption is required" schtick, especially against Demons, and Undead aren't too much different in terms of being an aberration that must be smitten into oblivion, and our Inquisitor is basically a God at Sense Motive, so I figured that he of all characters would've known this was a ruse. (He even rolled good on the Sense Motive.) The only thing they did smart in relation to this was put manacles on the BBEG in an attempt to keep him from escaping somewhere, but because the BBEG was considered helpless, it would've been more prudent to just execute him, especially with hard facts of the Undead guy being well-known for killing innocent people.
The last is a Chaotic Good Gnome Illusionist who, before we came across this encounter, was willing to burn down an insane asylum and a farm to defeat encounters (which the GM hinted would've caused the Paladin to fall, for associating with/condoning a pretentiously evil character/act). Granted, he prevented the PC death in the final battle, the fact of the matter is that I expected him of all people to not fall for this obvious ruse, especially with his murderhobo attitude prior to this. (Though, I have a feeling it's because we scolded him for that line of thinking before.)
I'm a Neutral Good Bolt Ace whom somehow got the ire of the BBEG (maybe he precluded me as the biggest threat since the Wizard was basically out of spell power by this point in the mission and he knew this), and would've died for it if not for the GM being forgiving after a recent PC death (which would've basically been nothing but an EXP grind with zero treasure to compensate for it, meaning eventually we'd just get out-geared by the enemy and we'd TPK anyway).

Darksol the Painbringer |

If you share this point of view with your character, you can probably solve this in-game. Even if you can't talk them out of doing these things, your character will probably start taking precautions from getting to deeply drawn in to the other characters' actions: It's perfectly reasonable to role-play "I don't think this is a good idea, but you guys go in, if you want to. I'll stay outside and keep watch".
Again, not being a dick about it. Just make it clear that your character is not suicidal.This way you avoid a TPK.
The funny thing is that I did something similar (i.e. I stayed in the back while the 3 melee PCs were in his face), and the BBEG still wanted me dead (the other PCs aren't exactly the most optimized, since they didn't dumpstat like I did).
Originally, I wanted to just move up and shoot him in his face, but because Coup de Grace is a Full Round Action, I couldn't take the proper action. (Also, I believe that because he's Undead, he's immune to the Fortitude Save or Die effect required anyway.) I also know that getting in an enemy's face that has a bunch of Save/Die effects when they hit you isn't exactly smart tactics, either. I was in a bit of a bind with what I wanted to do, so I basically let the PCs enact their apparent funeral since going in to help them out was similarly suicide.

mourge40k |

Hrm. So let me get this straight: You guys come across Mr. Undead, and handcuff him, after finding another plot hook. The fact that you have him completely at your mercy like this does mean you could easily kill him, yes. But seeing as you have this nice juicy hook that is obviously connected to him, it is also prudent to see if he knows additional information. Judging by the fact you use interrogate, I am assuming that this is the general line of questioning that occurred. Unless they were trying the whole redemption thing, I see less a case of Stupid Good, and more a case of not fully clearing a place and covering your backs before trying to get info.
Also, is this Rise of the Runelords? Because this sounds an awful lot like RotRL.

Darksol the Painbringer |

Hrm. So let me get this straight: You guys come across Mr. Undead, and handcuff him, after finding another plot hook. The fact that you have him completely at your mercy like this does mean you could easily kill him, yes. But seeing as you have this nice juicy hook that is obviously connected to him, it is also prudent to see if he knows additional information. Judging by the fact you use interrogate, I am assuming that this is the general line of questioning that occurred. Unless they were trying the whole redemption thing, I see less a case of Stupid Good, and more a case of not fully clearing a place and covering your backs before trying to get info.
Also, is this Rise of the Runelords? Because this sounds an awful lot like RotRL.
Well, him knowing more information wouldn't be wrong, but him telling us said information when it's quite clear he's Undead and doesn't care two figs about it, doesn't really leave us any point to interrogate him, since he's already dead anyway, and there's nothing we could've done to make him talk besides, well...talking back.