My alliance has two players who are active titan killers but we have problems with them in wars. All the time they are disqualified because do not have war team set up. Huge problem in this game is that we do not have proper communication tools and therefore it is very hard to tell people what to do, remind about titans, wars etc. I have idea. Do not know could it help but at least such people will not be disqualified anymore.
Raid defence team as War default team. It should work only if there are less than 5 heroes.