Going forwards:

Joint KR will get you deleted.
Sharing an op with an ingame ally/
having an offensive ally and both grabbing will generally not.
Coordination of any type....AB, GS, BR etc...

In the case of a grey area (like dr abuse or other things) we reserve the right to make judgement.

Yes it's arbitrary.

If you are unsure feel free to ask in private prior to taking actions or just don't do it.
If you think someone else is in violation, report them ingame.

Posting here will generally *not* result in moderator action.

messaging people and telling them you are dropping defense and they can farm away will be considered at this time under the coordination definition.
messaging people and telling them your break....is also a deletable offense.
If it feels like coordination..then it probably is coordination ;)

You should message me to make sure in the future to avoid being deleted. Or if you are unsure of any of the rules.