I believe that when a Wizard uses Staff of Defense or Shield, which are both immediate interrupts, she may ask the DM if the power will prevent the attack from connecting.
Does the same hold true when the immediate interrupt affects an enemy, rather than simply protecting an ally?
A player in our group has a Runepriest with the following power:
Word of Blinding Shield
Encounter Immediate Interrupt
Trigger: An enemy makes an attack roll against an ally.
Hit: target is blinded until the end of it's turn.
Would it be reasonable for the player to ask the DM if this power would cause the original attack to miss?
Is this all based on a misunderstanding of immediate interrupts?