Lord Chane, while I still disagree with some points, I can agree to your list of "betrayals". I consider what you mentioned bad style too, I would not do it, but paranoid as I am I would not rely on my allies to feel the same - unless their past action in the game have given me a more safe feeling.
But you have left a huge grey area. There still is a difference between using an alliance to move fleets in the systems of the soon-to-be enemy, braking an alliance without notice, or declaring every action XXX turns earlier, for example. This attacking without notice is getting even greyer when there have been tensions before, and you see large fleets assembled, and even expect an assault by your ally.
Another problem is the term "ally". In most games, you usually are "allied" via a TR treaty with everyone you are not at war with, just because of the mutual benefits of such a treaty. I do not consider such a mere formality a real alliance, for example.
I also think it takes a bit the tension, and thereby the fun, out of the game if you can rely 100% on everyone else in the game. Political maneuvering is nice
. But downright lying, and what else you described as "betrayal" is something different. Still, there is not only black or white, I think we agreee which is which, but what about the grey areas, which are the biggest? I do not think there are general, "right" rules of behaviour for any situation in the game. And no one has the right to impose his personal, subjective view of these grey areas on every other player. This is a matter of personal style.