You attacking a ship with a pirate flag - it's ok
You attacking a ship with a white flag - you become a rogue - anyone can receive some amount for your head.
Rogue ship is glowing red with lost souls flying over it.
It will bring more fight to aggressive players desiring PvP - everyone will hunt them for a reward.
At the same time it will show peaceful intentions of PvE looters
Once you attacked first - you have automatically raised a black flag, can't change it until battle is over
As easy as that.
