S'mon said:
I can avoid all this trouble by just _roleplaying the noble_ in-character - if he's a hothead he'll accept the challenge, a coward will order his guards to seize/slay the PC, etc. Only if I'm unsure of his reaction would the d20 come out - in this case maybe a Bluff roll to see how convincing the PC was in making the noble think it was a legitimate challenge, or Intimidate if the aim is to scare NPC into submission. Generally though unless the player requests a roll, I don't need one in this case.
So, does this make the charisma score of the character involved irrelevent? Is it possible to be so people savy to push the buttons of someone to the point where they break? Does being in a world where dragons live, and people can talk to animals, and teleport via trees make it any more likely? If one man can face down giants, and another command the very forces of nature itself, can someone pull a man's mind out of its senses?
The problem with just _roleplaying the noble_ is that there may come a point where what I feel is reasonable and what you feel are reasonable are different. Rules are good for those sorts of situations. Frankly, I'd probably trust your judgement on the situation, as long as I could point to my character sheet with the ridiculous cha, bluff, diplomacy, and intimidate and say "This helps, right?" Unfortunately, the answers I've heard on this thread seem to be saying "No matter what your abilities are, that option will never work". That's really where my only worry with RPing it out comes with, when people forget that there's some danger of having already decided how the situaiton will go, regardless of other influences. Maybe the lv 10 socialite can be able to pull a manuver off that seems too crazy to work.
I am glad you are on to the concept that rules help some people play, like the group I play in. Having the bank of rules gives us all something that we have to agree on, despite our different playing styles and methods. But, could you be considerate of my easily bruised feelings and avoid describing using the rules as a 'crutch and a comfort blanket', consider it more of 'having a mutually understood method for resolution'. It doesn't carry the implication that people who like rules are somehow less competent than those who role-play things out.

To me, it's less a crutch, and more a yardstick (though I suppose you could use a yardstick as a crutch in a pinch).
Really, there's never a single answer to judgement vs rules. It's all about finding what and where works for the situation at hand. Of course, we all know that.
But sometimes, when the situaiton is horriffically complex, and things could swing either way, it's nice to have a little chart of values that can be distilled into modifiers and then make an opposed roll. Or better yet, letting the player make an opposed roll.
Good conversing with ya, and thanks for helping me get my post count up.
Oh, and Kae, You lost me in there. When did the a question of the ability of a character to taunt someone into a duel have its point become 'A pesant would never do that'? Or are you pulling a fast one on me?
Reg, that was an interesting read. My only caution is to, as always, use caution when avoiding or minimising the rules, as it is possible for players to feel that they have no control over the situation. Should I link to one of those GNS classification things to be equitable?

Seriously though, I am not saying that you have to follow rules at all times in all things, or that DMs are incapable of making things up. I'm just saying that they can smooth things over. And if the game is about something, then having the rules of the game be about it helps.
Can you have politics in D&D? Heck yeah. But if I'm going to be running a game about politics, D&D would not be my first choice of system to run it in. Hm... Thinking about it, that sentence has really been what I've been wanting to say all along.