You're so missing the boat on this champ. An opt out button has nothing to do with participation. An opt out button does the same thing as leaders kicking and rejoining ppl that aren't interested in war. The end result is the same, you get to leave the few ppl who don't want to war out whether you kick and invite, or if you opt them out. It will not change participation. Show me why you think that.
If a person has a busy day and can't get war attacks in it doesn't matter if they were opted in or out. You're not even on the same page. Maybe you don't understand how an opt out button would work.
Opt out happens before a war starts, not during. If you include some ppl in war who get sucked up by aliens on battle day even after you opted out your sucky players, you won't get 100% participation. That all depends on how regular your players log in and use war attacks






