Basically problem Zelot has is that he allowed you to escort your trade ships with force, not to "make sure there aren't any"
Basically trader should be one gate lane away of the place where you are clearing the "threat". Or with the fighters.
If it's not, then you have an issue of breaking Kusari law as we all said already over and over so there's no point to quote it.
There's that saying "I give you a finger and you take the whole hand", but that would be going too far.
I am also interested to see how will this all be played out in roleplay, and honestly I'm happy with Swift's answers, but I see so many readers of this topic that could pick up on few tips on how to handle Kusari.
Because trust me, even if you remove Zelot out of equation, things would remain pretty much the same with the next emperor. Kusari just grows on you. The habits, the honor, the fact that dragon and knf can stand together and destroy a third problem. They're all so beautifully wise, and yet so ... stubborn when it comes to some things.
Diplomacy in it's purest form