Aren't banned.
They just don't work anymore.
A p war, basically had a clan full of players attacking an OSF(a pure spy with gold out) . They'd earn plunder, and eventually forfeit the war to the OSF side, the war tax from the war would go to the OSF side.
This exploit injected trillions of gold into KaW, and has been removed, you don't get payed war tax anymore, but in the form of mith now!