once declared ANYONE can register to be an attacker or a defender of the Node, the only condition is that all citizens of the Nodes are automatically registered as a defender.
Anyone who is a citizen of the Node is automatically registered as a defender in the siege on their home Node. Additionally, any vassal citizens are only eligible to register as defenders, they cannot register to attack. Neither group is required to actively engage in defense on Siege day, but defense is their only option.
tautau wrote: » Don't ignore the diplomacy that the sieged node will be doing - they might well have other nodes and various guilds who agree (for multiple diplomatic reasons) to help defend.