There is a discussion in my alliance about ex-members in rival team.
In the latest war there were 2 “ex-members” with the same name.
Is this fair?
What is SG policy about this people?
Can they join to another war?
Our leader forbid us to attack them because he read here they were thouger.
I dont know if this is true, I really dont know anything except they never fill up war chest properly.
A war is up to 30 players against up to 30 others players. Whoever is currently in the alliance is fair game to attack. Have at it! 
That’s crazy. I doubt he actually got the idea here because it makes no sense at all. The fact is that the ex-members either left or were kicked during the war. They can be attacked but won’t attack themselves so it actually helps your team to have them as an enemy.
But it prevents another team from kicking low people in the middle to give them an easier win. There’s reasons behind this change.
It is also an appropriate change; it fits.
If a player was in an alliance during matchmaking, their roster was counted in the matchup.
And if they leave or are kicked, they cannot join another alliance and be a participant for that war anyway.
The alliance losing their attacks is worse for it … but removing them from the battlefield would double that pain, because all their remaining teams would be worth more points than they were before, while the other side will get just as many attacks.