Ourph said:
See my remarks to silentspace above. I don't care about proving the existence of a trap, all I care about is not getting my character killed.
Then you don't enter the dungeon at all. If it's entirely reasonable for there to be an undetectable, extreme-save-DC insta-kill trap on a lever in a random room in the dungeon, then it's far more reasonable to assume that the same BBEG who installed that trap would have put an undetectable extreme-save-DC insta-kill trap on the entry to the dungeon, disarmed only by reciting the code phrase, which you don't know because he never wrote it down (being a smart BBEG). (Or, perhaps, it is disarmed by a special brand he had all his allies apply to themselves. Of course, he insisted on them doing a lot of bizarre things - wearing only purple, never wearing boots, self-mutilation, brushing their teeth... - so you can't be sure which of his crazy rituals are the key one.) Of course, there might well not be such a trap, but you just can't know. And if there might be, surely that's enough to warrant not going? Don't want to get killed, after all.
Oh, and before you say, "I know there's not a trap because people go in and out"... The place is filled with orcs, so people don't go in and out. Sure, the orcs do, but they've all got the brand. Of course, they don't know the significance of the brand, since it's now a tribal tradition, and they don't know which of the many tribal brands they have that does the trick. So, taking a prisoner won't help you. (Of course, there might well not be a trap. In which case taking a prisoner is pointless. But you can never be 100% certain, so...)
If the goal is to open the secret door and it's possible that pulling the lever opens the door then I'll find some way to pull the lever while putting my character at the minimum risk possible. I don't care whether there is or is not a trap. What I care about is that the trap is a possibility and if there are ways to avoid the possible risk pulling the lever represents I'll take advantage of them.
Okay, how do you deal with the
possible risk of simply entering the dungeon? This one doesn't have a nice lever to scream TRAP at you, but it's a possibility (as much as the lever is).
The fact is, the DM could easily install absurd traps at the start of every dungeon. That's certainly the most likely place for them. And he could easily construct his traps so that they are undetectable, unsaveable, and instantly lethal. And he could construct the rest of the dungeon so that the whole thing makes logical sense.
But a DM who does so makes it impossible for the party to adventure at all. So no sane DM does that. But, of course, that's a metagaming concern, so shouldn't be taken into account.
My point about negative data is simply that you can never prove with a Search check that no trap exists, so (from my perspective) acting as if a Search check is absolute proof relies on the metagame knowledge that "taking 20" plus "challenges appropriate to level" equates to proof positive that a trap isn't present.
I'm not talking about "absolute proof". I'm talking about reasonable assurance.
The party will know whether they are in over their heads or not. I've been through that before. Either the trapfinder has successfully found all the traps in this dungeon so far, or he has not. If he has, then the monk has no reason to doubt him.
In general, a layman should not doubt the assessment of a skilled professional, in said professional's area of expertise, without good reason. And, unless the rogue has missed traps in this dungeon before, no such reason exists.
Would the monk stake his life on the skills of the rogue?
Well, if the McGuffin is found, perhaps not, since there's no need. But, if the McGuffin has not been found? Bearing in mind that, unless this is their first adventure together, they have a history of trusting one another, and often when their lives are on the line?
I would say it is reasonable for the monk to trust the assessment of the rogue. There's no good reason not to.
You might well argue, "but the McGuffin is found". That's true. However, unless the trap mysteriously sprang into existence when the McGuffin was found, the possibility exists of it being found first. And if the trap is fair after the McGuffin is found, it must be fair before the McGuffin is found. So, kindly deal with that case.