I would say that this falls into the common sense category. If you or your character has to ask yourself, "Should I be writing this?" or "I wonder how much trouble this will get me into." or "I hope this slips by without a GM noticing." then the answer is likely "No."
There is no system of law -coded- right now, but that does not mean you assume there are no laws, or you are above them. I was just told yesterday by someone with maxed stats that they can do anything they want because they could defeat any guard sent to arrest them. Foolishness and idiocy. If one guard was defeated, ten more would come. Defeat them, and the rest of the army comes. One way or the other, you go down. The same goes for writing. Just because no one -will- come to arrest you right now, it does not mean they would not.
Good RPing means playing to bounds coded in the game, as well as those that are not.
As for 'freedom of speech', don't count on it. One of my characters, who is a law abiding and upstanding citizen, was killed by an Octarch's guard for questioning the Octarch's motives in putting citizens in danger for his own benefit.