Anything not contained within the rule book is a house rule. 90% of what you guys are presenting are simply that, house rules.
I'm afraid I still take issue with that.
I would say what have been presented are not house rules, but interpretations. There's a difference.
People haven't said "that doesn't work, I'll change it"... they've said "How does this work?"
For me, I find using the Rapid Shot example (which has turned up in a Sage Advice or FAQ entry, from memory) clarifies the way retroactivity works in 3E.
In similar fashion, if someone elected to use a double-move to withdraw from combat without provoking an AoO (first square unthreatened rule), and before covering their base move distance (say 30') found an unexpected situation - an invisible opponent, for instance... I would rule that they could take no action other than a Move (not MEA), or stopping.
If I allow them to change their mind and attack the invisible opponent, then the square they started in
was threatened, the rogue they were retreating from
did get an AoO, the rogue's Hamstring feat halved the character's movement rate, he never reached the invisible opponent and therefore didn't make an attack, in which case the rogue didn't get an AoO after all...
The Rapid Shot precedent says that one cannot alter one's intended actions mid-round
if the alteration would retroactively affect actions that have already occurred.
With Haste you can move, attack, and then decide based on results to move again -
as long as your initial move did not prevent any AoOs by being a 5'-movement-that-was-your-only-movement-for-the-round.
You can make a single attack and then choose whether or not to continue with a full attack -
as long as nothing about your full attack would have modified that first attack roll.
You can move your speed, and then decide whether to continue moving or do something else -
as long as you did not treat your initial square as unthreatened.
Thus is paradox avoided, and it's not House Rule, it's Rule Interpretation.
-Hyp.
