I find that really have to believe as usually at least one occurs within the first few turns.
What factions have you played and at what difficult level?
And how many factions are you are war with by say the 10th turn of the game?
I'm currently playing France on Easy Campaign Difficulty just to test if it affects the volume of Random DOW's. It didn't but the 1.3 patch does seem to have results in my game going relatively quiet. I've only had 1 x Random DOW's in the last 10 turns or so, from Austria that couldn't actually reach me so I avoided the event by reloading and replaying the end of turn. Britiain offered me a trade for Kentucky which I refused but it didn't follow through. Britain is bankrupt in my game anyway simply because Prussia stuck a fleet in Greenwich on turn 2 and they never sent an army from London to liberate the port.
The other thing I've noticed with 1.3 is that now the pirates attack the Trade Ports none of the AI factions send any ships there. France actually has all the trade theatres to itself, even though I deliberately restrict myself to using no more than one Trade Post in each theatre, the others just sit empty.
Bookmarks