I have a saying I like to use in situations like this.
When the cat is away the mice will play.
Give it time, let the "mice" come out of hiding, the cat, or in this case the psychic octopus, will eventually catch them.
The mods allow users to enter the number of troops/levels for the sandbox attack. A new account can practice on a base with 500 level 5 Pekkas if they wanted. So the main character uses this newbie account to enter their troops, levels, heroes and practice attacks on their assigned base in war. I'm not sure about traps, if they can still see traps in sandbox or add them manually. Unless the base has already been attacked then the mod can see everything I believe. After they have it practiced, they log on their main account with a clean device and attack in war for real.
SC needs to temp ban everyone in the clan if a certain number of newbie accounts get banned. Even if the rest of the clan doesnt cheat, they certainly know about it and are choosing to benefit from it.