They have no treaty with Knights of Ni. Which is why it caused a lot of head scratching, because aside from moralistic bs they had no reason to be involved. (Neither did most of the other involved parties either, but that's a different point altogether).
The only treaty Knights of Ni had was with MASH. And as per the MASH announcement regarding this, half of their gov didn't even know it existed. It had apparently been carried over from a merger, and resigned in an embassy, but never got posted on OWF, the Wiki, or anything else, and MASH had to go digging to find it. Apparently they had no communication with each other since signing that treaty some 18 months ago so it just became forgotten.
Seriously guys, with how confounded the treaty web is do you think Athens would have been stupid enough to raid anyone with even one public treaty? I know global opinion of Athens is at an all time low, but they're not -that- stupid.