In Col there were instances when you could attck (or be attacked by) other Europeans while remaining officialy at peace with them.
One example is a city where privateer is docking - it can be attacked or even occupied with no ill effect on the official relations with that faction (After all the official statement of every faction in the game is "WE NEVER CONDONED PIRACY" ;) )
It's not so new, if it hasn't been implememnted in Free Col yet, I'm sure it's waiting in the queque.
But now testing the Old game I discovered, thst this rule is also working on sea. I had peasce with the French (Actually to be precise, it was The Reoublic of Quebec, since the bastards have bacame independent) My Privateer ended it's turn next to Quebequian Frigate, so I sent my frigate on that field to prevent the Privatter from being attacked and possibly sunk, but the Quebequians attacked the BOTH ships anyway. Luckily they lost :) The Quebequian Frigate was sunk, the peace remained uncharmed.