[Mobhack]

You cannot stop scattering fires going into cover, since that is built into the game system. Does not matter if it is direct fire or indirect - no notice is taken of any blocking terrain when scattering fire. Its been that way forever, and would need a fairly big rewrite of the firing code to fix.

As to human players misusing Z-fire, then I think a house rule of say "No more than 12 bursts of Z-fire permitted per turn" should curb any players who go to extremes. In a competition, the save game of anyone ignoring this could always be forwarded to the umpires for action.