Oh, so you got the ninja assassination event and are bordering Jomon?
It isn't connected, actually. The event is independent of Jomon. It's like the bands of Ronin which are also, while Jomon-themed, not actually caused by Jomon (besides perhaps them being in the game, but then you'd get barbarians instead probably and those are honestly worse in my opinion).
That being said, as for remotes, if you can tell who they're coming from and its being sent at you, then you are well within your rights to call them out on it as a violation.
What you do have to worry about though are those Mind Hunts when there are 4 astral nations running about.