Alf O'Mega wrote:
So it's completely valid to engage a unit you can't see with a potential +4 combat res due to numbers and BMs? That seems a little odd?
True, and I would be inclined to think it's an oversight, but the rules don't actually say anything about LoS in the relevant parts (i.e. what happens if nothing makes it into 15cm, and what happens when all of the "directly" engaged units are destroyed - in both cases only the range is mentioned).
That being said, it's pretty rare. In the case of defenders within terrain, it's impossible: if the attacker can get within 15cm, then the defender can get within 10cm thanks after counter charging. So it can
only happen with terrain features that are both impassable to the defender AND blocking LoS. If the terrain is also impassable to the attackers then it would also have to be < 15cm wide. Examples would include an infantry formation attacking a vehicle formation that is hiding behind a building, or an engagement between two formations either side of a fortified wall.
Given how infrequently it comes up, whenever it has happened in games I have played it has been sufficient to just agree not to do it.