I think it's difficult to get an answer because policy is difficult. Every case should be treated on its own merits, but the game is complicated enough that there are always exceptions to the general case/policy.
I'm sure everyone wants to know the boundaries of someone they're competing with. Setting expectations can help avoid conflict, especially if they relate to the case in point. Many alliances set 'lazy expectations' - detailed conditions that will and will not be tolerated, and I say "lazy" because they do not consider all the possibilities of a specific case that a player will be curious about. Besides, these policies must be sought-out, and for that reason, they're effectively inaccessible.
If players want to operate with transparency, and avoid wars over silly misunderstandings, then those players should enter situations carefully, being aware of potential conflicts, and then open the diplomatic channel (I mean talking PvP, rather than sending in the Assassins!) to agree boundaries.
So, the short answer to nearly everything is, "Every case is different; let's talk about this one."
(edit, for spelling correction)
Edited by Albatross - 18 Sep 2012 at 02:04