Quick script:
package kbn
{
function serverCmdBan(%client,%n,%n1,%n2,%n3)
{
%n3 = %client.name @ " has banned you for:" @ %n3;
parent::serverCmdBan(%client,%n,%n1,%n2%n3);
}
};
activatepackage(kbn);
Not sure how many args are in serverCmdBan but the last one is the reason.