[MaxWilson]

Atul,

According to the manual, there is no chance to hit "empty space" anyway. At least one target will be selected, and the to-hit opposed roll will then take place. It is true that the to-hit roll takes into account how crowded the square is; maybe that's what you're thinking of? That's not separate from lightning bypassing the shield parry, though, because crowdedness, fatigue, and shield parry are all modifiers to the same contest.

-Max