This topic is to explore Spastic's suggestion of taxing (or fining) the plunder of members of own nation.
Option 1) Nation plundered (All nations or specific nation)
Option 2) Percentage of fine (1%-75%)
Option 3) Minimum fine (0 - 250,000 gold)
Option 4) Maximum fine (250,000 - 1,000,000 gold)
This offers a diplomacy tool for the governing council as well as a means to generate revenue for the coffers. The numbers I used are arbitrary, as I simply wish to open the idea for discussion.