Filibusters were unofficial, often civillian invasions of foreign territories, such as the William Walker episode in Nicaragua and the Bear Flag Revolt in California. They were rather common in Latin America in the 19th century as American settlers attempted to detach provinces from the Latin American republics. Some historians place the Texas Revolution in this category. I seem to recall similar incidents in parts of South Africa as well.
Similarly, "sub-imperialism of the periphery" is a phenomenon whereby local colonial or frontier conflicts, strategic concerns, etc. led to imperial expansion without authorisation from the central government.
I think it would be interesting for the game to reflect these events, perhaps with events by which, under certain circumstances, areas might suddenly come under an empire's control - along with the concommitant native unrest and diplomatic complications.
Similarly, "sub-imperialism of the periphery" is a phenomenon whereby local colonial or frontier conflicts, strategic concerns, etc. led to imperial expansion without authorisation from the central government.
I think it would be interesting for the game to reflect these events, perhaps with events by which, under certain circumstances, areas might suddenly come under an empire's control - along with the concommitant native unrest and diplomatic complications.