Never say never, go figure what's going to happen if they found something interesting in what I've said so far...
Bounties, crimes and security ships may be or may not be part of the equation (i.e. if system is anarchy, Delaine space for rank 5 pledged to the Archon or even folks flying with "crimes off" as most of the CMDRs in combat ships do), as I've said before when there's a BGS war between player factions, whatever eventually happens in open does count.
In an anarchy system (which are few and far between) things are a little different, but as far as i'm aware, killing of ships still lowers the security of the leading faction, even if they are anarchy.
Anyway, what would be the point of a head to head conflict even in anarchy space? It doesn't resolve anything BGS wise.
In a BGS war its all about doing those missions for max INF or other INF affecting activities.