This is the reason that rules lawyers, though they do serve a purpose, can be so annoying. No offense, Hypersmurf, but I prefer rules JUDGES. Rules judges seek to hew to the spirit of the rules, and arrive at just and reasonable decisions.
As an example, let us take a rules lawyer's look at this whole invisiblility/concealment question, then let us follow that with a rules judge's approach. Quoted sections are quoted directly from the 3.5 rules.
"Table: Attack Roll Modifiers
Attacker is . . .Invisible +2 (The defender loses any Dexterity bonus to AC. This bonus doesn’t apply if the target is blinded.)"
"Table: Armor Class Modifiers
Defender is . . .Blinded –2 (The defender loses any Dexterity bonus to AC.)"
From this we see that a Blinded defender and Invisible attacker comes to the same thing. That actually makes sense. And they even go so far as to point out that an invisible attacker gets no further bonus against a blinded character. The penalty only gets applied once. How enlightened.
As a rules lawyer I decide that there is a condition that can be granted to an attacker called 'Invisibility. and a condition that can be granted to a defender called 'Blinded'. I note that the result of those conditions are identical. The defender loses his Dexterity bonus and the attacker is effectively +2 to hit.
As a rules lawyer, I now read the section on Concealment and very carefully note that nowhere does it say that a concealed creature gains the condition 'Invisibility'. Nor does it say that a creature attacked by a concealed creature gains the condition 'Blinded'. I am forced to conclude that attacking with 100% concealment grants no bonus.
But wait! I am not done by half! I now look at the spell See Invisibility.
"See Invisibility
Divination
Level: Brd 3, Sor/Wiz 2
Components: V, S, M
Casting Time: 1 standard action
Range: Personal
Target: You
Duration: 10 min./level (D)
You can see any objects or beings that are invisible within your range of vision, as well as any that are ethereal, as if they were normally visible. Such creatures are visible to you as translucent shapes, allowing you easily to discern the difference between visible, invisible, and ethereal creatures.
The spell does not reveal the method used to obtain invisibility. It does not reveal illusions or enable you to see through opaque objects. It does not reveal creatures who are simply hiding, concealed, or otherwise hard to see.
See invisibility can be made permanent with a permanency spell.
Material Component: A pinch of talc and a small sprinkling of powdered silver."
As a rules lawyer I notice two things. Firstly, nowhere does the spell say it negates the bonuses an invisible attacker gains when attacking me. Secondly, nowhere does it say that it removes the condition 'Invisible' from any attackers. I can see them, but they are still 'Invisible'. In fact I can even TELL that they are 'Invisible'. As a rules lawyer, I am forced to conclude that invisible attackers still get their 'Invisible' bonus when attacking creatures that have cast See Invisibility. I am also forced to conclude that I am probably an idiot.
I now cast my rules lawyerly eye toward the Blindsight ability.
"BLINDSIGHT AND BLINDSENSE
Some creatures have blindsight, the extraordinary ability to use a nonvisual sense (or a combination of such senses) to operate effectively without vision. Such sense may include sensitivity to vibrations, acute scent, keen hearing, or echolocation. This ability makes invisibility and concealment (even magical darkness) irrelevant to the creature (though it still can’t see ethereal creatures). This ability operates out to a range specified in the creature description.
• Blindsight never allows a creature to distinguish color or visual contrast. A creature cannot read with blindsight.
• Blindsight does not subject a creature to gaze attacks (even though darkvision does).
• Blinding attacks do not penalize creatures using blindsight.
• Deafening attacks thwart blindsight if it relies on hearing.
• Blindsight works underwater but not in a vacuum.
• Blindsight negates displacement and blur effects.
Blindsense: Other creatures have blindsense, a lesser ability that lets the creature notice things it cannot see, but without the precision of blindsight. The creature with blindsense usually does not need to make Spot or Listen checks to notice and locate creatures within range of its blindsense ability, provided that it has line of effect to that creature. Any opponent the creature cannot see has total concealment (50% miss chance) against the creature with blindsense, and the blindsensing creature still has the normal miss chance when attacking foes that have concealment. Visibility still affects the movement of a creature with blindsense. A creature with blindsense is still denied its Dexterity bonus to Armor Class against attacks from creatures it cannot see."
Here I have to stretch my rules lawyerly obtuseness to its limits. For, Blindsight does indeed state, "This ability makes invisibility and concealment (even magical darkness) irrelevant to the creature..." However, nowhere does it say that it negates the bonus granted to an invisible attacker of a creature with Blindsight. And while invisibility may be irrelevant to the creature with Blindsight, the invisible attacker still has the 'Invisible' condition, so the invisibility is not irrelevant to the attacker. As a rules lawyer I must now conclude that an invisible attacker gets a +2 bonus and the defender loses his Dexterity bonus, even if the defender has Blindsight. The rules do not explicitly state otherwise. I also conclude that I am an even bigger idiot than I thought.
Feeling pretty cocky now, I am ready to take on Blind-Fight.
"BLIND-FIGHT [GENERAL]
Benefit: In melee, every time you miss because of concealment, you can reroll your miss chance percentile roll one time to see if you actually hit.
An invisible attacker gets no advantages related to hitting you in melee. That is, you don’t lose your Dexterity bonus to Armor Class, and the attacker doesn’t get the usual +2 bonus for being invisible. The invisible attacker’s bonuses do still apply for ranged attacks, however.
You take only half the usual penalty to speed for being unable to see. Darkness and poor visibility in general reduces your speed to three-quarters normal, instead of one-half.
Normal: Regular attack roll modifiers for invisible attackers trying to hit you apply, and you lose your Dexterity bonus to AC. The speed reduction for darkness and poor visibility also applies.
Special: The Blind-Fight feat is of no use against a character who is the subject of a blink spell.
A fighter may select Blind-Fight as one of his fighter bonus feats."
Ack! The rules lawyer in me is defeated! Blind-Fight very specifically and in great detail, negates the bonus a melee attacker with the condition "Invisible" gains on me. However, I take solace in the fact that I can now crow, "Well, look, Blind-Fight clearly states that it negates the bonus an invisible attacker gains on me. If they meant Blindsight to do the same thing, they would have stated it just as clearly in Blindsight. " So, I lose this case, but I use it to seal my victory over the hated Blindsight. I am starting to feel that I am less of an idiot. Either that, or the rules writers occasionally get one right.
END OF RULES LAWYER APPROACH
START OF RULES JUDGE APPROACH
Why, I ask myself, do invisible attackers gain a bonus? Why does this bonus have exactly the effect as the penalty inflicted upon a blind defender? What does a defender being attacked by an invisible opponent have in common with a blind defender?
I know! NEITHER DEFENDER CAN SEE HIS ATTACKER! I expect that the real issue being addressed here is not being able to see your attacker. I feel certain that the framers of the rules intended the +2 bonus for attacker and loss of Dexterity bonus for defender be applied WHENEVER THE DEFENDER CANNOT SEE THE ATTACKER. All this talke about attackers having the condition 'Invisible' or defenders having the condition 'Blinded' is so much crap and a waste of time.
Okay, the correct ruling is clear, the defender's Dexterity bonus to AC should be lost whenever his attacker is unseen. So See Invisible and Blindsight ARE effective against the invisible attacker, even though the rules as written say otherwise. Similary, 100% Concealment or Hidden works just as well as 'Invisible' for gaining the invisible attacker bonus. Not only is this clear, but it is just and fair.
But the rules lawyers will come at me with their 'rules as written', 'letter of the law' nonsense that ruins so many games. I must do some rules lawyering of my own to defend my decision in a way that the rules lawyers will understand. So, instead of wisely sleeping, I turn my bleary eyes once more toward the SRD.
"DEXTERITY (DEX)
Dexterity measures hand-eye coordination, agility, reflexes, and balance. This ability is the most important one for rogues, but it’s also high on the list for characters who typically wear light or medium armor (rangers and barbarians) or no armor at all (monks, wizards, and sorcerers), and for anyone who wants to be a skilled archer.
You apply your character’s Dexterity modifier to:
• Ranged attack rolls, including those for attacks made with bows, crossbows, throwing axes, and other ranged weapons.
• Armor Class (AC), provided that the character can react to the attack.
• Reflex saving throws, for avoiding fireballs and other attacks that you can escape by moving quickly.
• Balance, Escape Artist, Hide, Move Silently, Open Lock, Ride, Sleight of Hand, Tumble, and Use Rope checks. These are the skills that have Dexterity as their key ability."
Aha!
"Armor Class (AC), provided that the character can react to the attack."
If the attack cannot be seen, the character cannot react to the attack. An attacker that is hidden or has 100% concealment cannot be seen, so the defender cannot react to the attack, hence loses his Dexterity bonus to AC. Even a rules lawyer has to go along with this one, however impermeable he might be to common sense.
For what it's worth, it is obvious that a defender who is held, bound, webbed, etc also loses his Dexterity bonus to AC, since he cannot react to the attack.
However, the rules lawyer will no doubt now go on to say that Uncanny Dodge does not prevent you from losing your Dexterity bonus to AC versus hidden or concealed attackers, since only invisible attackers are mentioned, not hidden or concealed onces. Sigh. It never ends.