During uncartel defense operations, voting all 4 fellows is required to obtain maximum reward, as you can see below. A light penalty is applied on voters too deeply involved with cartelisation. If you complete your votes on all fellows, a vote refund 1 lisk is given if your stack is above 100 lisk. It will be done automatically without further action.
Payouts occur only when full votes on fellows. All these procedures will be removed when no cartel will threat any more.