Am I not responsible for collateral damage?

In a recent play-through of Alpha Centauri I encountered some strange AI behaviour:

As governor of the planetary council I lifted the atrocity ban. Then I allied with one faction and dropped a couple of planet busters on the rest. I quite enjoyed that, got a bit carried away and some of the cities of my ally accidentally got caught in the blast waves. Funny thing is, the ally didn't complain at all.

So why did I get away with it? Does the lifted atrocity ban allow for collateral damage? Or do allies not care about collateral damage? Or does the AI never care about collateral damage?

From my experience I think the AI may not have any check for collateral damage of this kind, and with the atrocity ban lifted they only care about the PB if it's dropped in their territory. So you're probably free to wipe out allied bases so long as there's an enemy base near enough to target.