These days, it’s often seen on maps where battle zones, such as gray zones, are inaccessible.
These players are deliberately aiming at them, which is detrimental to game players.
At this time, the kill score of kills from the so-called gray zone outside the battle area should a 0.
Only kills within the gray zone of the appropriate engagement area should be scored .
maybe even block shooting from that area with a message like: secure your weapon in a friendly area.
Also shots into that area should not do any harm. This may lead to some hilarious situations 
I would like that.
Same goes for the spawn bombing. Shooting in and out of spawn area should be blocked. Also for mortars and artillery calls. I mean you cannot call arty on spawn nor can you call arty or fire a mortar, while you are inside the spawn area. This would also slow down the pace of the game a bit and offer opportunities to be more tactical.