The DM is well within his rights to say the shoppers are to frightened and undecided to make this decision
That's my point. NPCs just shouldn't always make be making the best metagaming decisions. If there's a psycho unleashing blasts of magic all over the place they'll think "Holy




and thus not give any advantage trough the feat. This does not mean they are suddenly your enemies and take damage,
No, it means exactly that. Not an ally equals an enemy. 4e is this black and white in this regard.
There exists a case were a creature is neither an ally nor an enemy. You could call this condition neutral, but for all rules purposes not-ally and not-enemy is the correct appellation. In common parlance, this would be called a neutral or bystander.
And D&D makes it clear that it doesn't acknowledge this real world condition