The Crimson Binome
Hero
My point is that you're making seven skill checks, and rolling the d20 seven times. If a rogue doesn't fail on a 1, then the best possible chance for the group to get past those traps unscathed is 100%. If they fail a check on a natural 1, then the best possible chance for the best possible group is slightly worse than 70%.To answer your questions as best I can, to make it through those seven traps unscathed under the best possible conditions (which I will assume includes a single rogue with skills built to deal with traps), I'd be comfortable with 95% or higher.
I'm not sure I understand your follow up question as to how I would represent that, but I would be plenty happy to watch a rogue buzz through all those traps with a 95% chance of success.
You go directly from "Yeah, you're fine, don't worry about it," straight to "Don't be surprised if something goes wrong, it's basically a coin flip." There is no way for the mechanics to say "You're probably going to be fine, seriously, but you never know." If you think the best possible chance for a group to get past these traps under optimal circumstances should be 95%, then giving them a 100% chance is closer to that than giving them a 70% chance.
It's been a while since I've run a solo dungeon, and I don't think I've ever run one for a rogue (or thief). I'm also generally opposed to creating dungeons with the intent of challenging specific characters, because it can invalidate their character choices - why would they bother being proficient in thieves' tools, or choosing it as one of their expertise skills, if they knew I was going to take their modifier into account when designing the dungeon? If I did take up the challenge of specifically designing a solo dungeon to challenge a rogue, then I would use a much broader range of DCs for the various traps and locks - again, because I wouldn't want to look at their character sheet beforehand, and because I would want whatever their modifier ended up as to actually matter.But I will ask you, a hypothetical. Say you're running a solo dungeon for a rogue with his trap skills geared up with Reliable Talent to the point where he automatically succeeds at DC 20 traps, which are the max DC's presented in the dungeon. How would you handle it? Would you adjust the DC's to present more of a challenge? Would you let him just sail through them all? Would you perhaps make time a factor, as others have suggested? Please understand that I'm not being factious in the least. I'm honestly interested to know. When talking about the "thief robbing a whole town" scenario many people suggested interesting potential side plots that could arise to complicate the thief's life. Would you try to do the same in a dungeon setting, and if so, how?
I will go on record as saying that I'm not a fan of dungeon traps, just on general principle. They either strain the laws of physics with their mechanical efficiency, or they add gratuitous magic to a setting that probably already has too much magic in it. I will include some in the obvious sorts of places when I design a dungeon, and I don't mind if I'm the designated trap-monkey when I'm a player, because they are an expected part of the genre.
Traps in fifth edition seem even more pointless than in other editions, since they can't really inflict lasting damage - similar to combat encounters, you'll be fine after a nap - and they aren't even worth XP, so I honestly have no problem with a character just breezing past that aspect of the game. Not everything needs to be a contest, and if someone feels very strongly that they don't want to worry about traps, then I'm happy to oblige them on that. (Likewise, if someone makes a character with a very high AC, I don't feel obligated to challenge them on that; there's more to the game than whatever singular aspect the character has specialized in.)