Why am I not surprised.
For instance, charge is a single action - so by this account you can't ready an action to (say) stab a person with your longspear as s/he charges you from 20' away - because before the action the charger is outside reach, and once the action is completled the charger is adjacent and has already rolled his/her attack against you.
Preparing against a charge is covered in a section below what I quoted, it didn't seem appropriate concerning spells and thus I ignored it at the time. Beyond that the definition given at that time is that you set against the charge, not that you are avoiding the effect of the charge and running away to make sure the charge didn't hit.
Also, this sentence seems confused:
If the triggered action is part of another character’s activities, you interrupt the other character.
How can the triggered action be part of another character's activities? Presumably what is meant is "if the
triggering action is part of another character's activities." Or, perhaps "if the
triggering condition is part of another character's activities".
Right? So in my above analogy.
Breakdown of events (according to Starfox):
Character A: I want to prepare to run way if targeted by a fireball.
Character B throws fireball. Character A runs away and evades because he is not there.
Breakdown of events (per SRD that I am trying to explain):
Character A: I want to prepare to run away if targeted by a fireball.
DM: Set your condition.
Character A: Um...? When I see the glowing emination of the fireball.
DM: Okay..
Character B: I throw a fireball.
Character A: I run --
DM: Roll reflex, save half.
Character A: But I ran away..
DM: Right, but your condition is to move when you see the glow. But as it is an instantaneous effect you only see the glow AS it happens. You can't move AS something is happening. Only BEFORE it happens. Ergo, if you try and run away BEFORE he throws the fireball (but presumably after he cast, and is then forced to finish) then he can re-adjust and hit you in your new square. You can't act AT THE SAME TIME as the effect, only BEFORE. So.. roll reflex.
In any case, hurling a fireball bead would seem to be an event that is part of a spellcaster's activities, and a reasonable thing to ready movement in response to.
See above.
If someone wants to spend their standard action readying a move action in response to an enemy's fireball, I don't see what is wrong with that. I certainly don't see how it is going to "break the spell economy or otherwise screw casters or anyone else out of their actions" (per @
Tovec upthread). The caster still gets to cast fireball - they haven't lost their action. But if they wanted to be guaranteed to hit the dodging person, they should have changed a Single Target rather than AoE attack spell.
No, if they want to hit 6 people and this prepared action thing goes through then they can end up hitting 5 people with the 6th getting away, OR they can hit that one person who moved outside the effect. The spell economy should not be broken because readying an action is not intended to completely screw someone midway through an action, it is supposed to allow the first person to react differently than they otherwise would have. That is especially why the CONDITION set is so important when readying.
Random Example:
I prepare to run away if someone comes through the door. HOW? Condition could be as soon as I see them, I run away. In which case then they are already on the other side of the door and can do whatever they want at that point. I could then interrupt their turn and act. This would have been the same as me running BEFORE they entered the door but in that case I am unsure if they are going to. If my condition was different, as to allow me to move before the guy entered the door (so he didn't see me let's say) then that guy is still on the other side of the door when you move and is no longer "required" or forced or forfeitted into going to the other side of the door, just because you were there and he can then change his mind.
Either way; I see this as a person wanting to clearly abuse the spirit and actual meaning of the rule in order to break it. That is wrong (IMHO) via both RAI and RAW. Ultimately each game/player/w/e can do whatever they want but I have given my response to the question given as well as I can.