I looked through the rules as it is, and I did not see anything about what constitutes knowledge "in-game" and "out-of-game". Ie, the information presented in combat threads,Inner Sphere/Clan Chatterweb news reports, and Faction threads. Also, with this delineation in black and white, everyone is starting off on the same footing.
Personally, News Threads are common knowledge for everyone. [RP] and [RP/MM] threads are common knowledge for involved factions. IC Faction threads are not. Negotiations between factions should be done in Turn#[RP] threads.
Players using information form IC Faction Threads or [RP] threads their factions are not involved in get Infrastructure blewed up.
I say this because I have seen far too much "behind the scenes", ie PM "negotiations" that never manifest themselves IC in any way, shape, or form save combat threads. IMPO, this smacks of meta-gaming. I know not everyone sees it that way, and I am not accusing anyone of cheating. It is just my personal belief.