Ad-Libbing
AD-LIBBING
Any time your character says what another character is doing without conset from that character's player, it's called "Ad-Libbing" and is not allowed in the game.
Backstory and what happens outside of action posts count as well, unless the character in question is not controlled by a player. (Ad-Libbing counts as well for Mod-controlled characters, the Minister of Magic, Dumbledore and Voldemort.)
Example:
::sees Fred go into Diagon Alley from the Leaky Cauldron::
~~~
This is assuming not only that Fred was headed toward Diagon Alley, but also that he was in the Leaky Cauldron. There could be some kind of plot that Fred's player is working on which says he wouldn't be there. If this comment is discussed prior to the posting, then there isn't a problem.
Another Example:
::sighs:: After the incident at the lake last year with Luna, everything's a little weird. ::nods, remembering the time he kissed Luna out by the lake::
~~~
If the backstory of Luna and whichever character is speaking was not pre-approved by Luna's player, then this post is ad-libbing that backstory.
Yet Another Example:
::heads out to the pitch for practice, after recieving an owl from Harry saying he needs to improve his Quidditch Skills or he'll be kicked off the team::
~~~
This is ad-libbing that Harry sent an owl to him, unless the owl was actually sent.
It's rather self-explanatory.
Bottom Line: As mentioned before: If you mention another character's actions, feelings, expressions, or words in one of your own journal entries, owls, action posts or comments, it's "AD-Libbing" and therefore against the rules.