[@Willy Vereb]

I think that a good way to avoid these "coincidences" is to enforce a rule which requires any environmental destruction with beneficial results to be either intentional or situationally unavoidable. If the attack isn't aimed specifically to do collateral damage, then it will always do the minimal amount of it possible. 

For example, the attacker may gain an advantage by striking a building support and collapsing said building onto their enemy. If there was no prior mention of the target being near the support, then an attack aimed solely at them will have no chance of hitting it - it is neither intended to strike said support, nor does the context of the previous posts make hitting it unavoidable. 

If the target were to be standing right in front of it, then the support is within reach of the attack and will be affected by collateral damage, whether intended or not. Same if the attacker plans ahead and strikes from an angle that permits hitting the support.