Since I think it's important information, LJ has recently (read: yesterday evening) posted a response to inquiries about the banning of members and clarifying what is and is not allowed. You can find this as the latest post at lj_biz. The comments are nearing 5000, which is the maximum, so feel free to discuss anything in this post if you like.
Also, remember to friends lock posts of fanfic/fanart that have the pairing in any sort of sexual or romantical relationship (if it's questionable, better to f-lock then to not). If the fanfic/fanart is gen, you do not need to f-lock it, but if you like, you're more then welcome to.
Being able to look a little more over the recent post and what LJ says, so far it looks like they are more going after fanart. There are so many links to read, and I'm not sure what their stance is on fanfic yet, specificly what the stance is on two underage characters, one underage and one above age, or incest. If anyone has a link to where LJ talks about these issues specificly, please link to it here. The more informed, the better.
As nixwilliams stated in the comments, LJ can read any locked or private entry. Granted they aren't going to be out policing communities or personal journals; from the way I understand it, an abuse report needs to be issued, and the report will be followed through with. F-locking can only go so far. However, as stated above, I'm not sure how LJ feels about fanfic at this time. Right now I'm leaving it up to still please f-lock the fanfic (though it is up to you to f-lock or not).
Speaking of fanart, I definitely want to point out a specific thread in the post on lj_biz. Per comment here, LJ reports material that is considered child pornography to authorities (NCMEC). "Under federal law, child pornography is defined as a visual depiction of any kind, including a drawing, cartoon, sculpture, or painting, photograph, film, video, or computer-generated image or picture, whether made or produced by electronic, mechanical, or other means, of sexually explicit conduct, where it depicts a minor engaging in sexually explicit conduct and is obscene, or depicts an image that is, or appears to be, of a minor engaging in graphic bestiality, sadistic or masochistic abuse, or sexual intercourse, including genital-genital, oral-genital, anal-genital, or oral-anal, whether between persons of the same or opposite sex, and such depiction lacks serious literary, artistic, political, or scientific value." (From the NCMEC, link given here.)
From my understanding, both coffeechica and markf are employees of LJ. Fanart is not exempt from this definition. Posting fanart of this nature can definitely put one in a bind, to say the least, whether it be in this community or anywhere else on LJ. Again, the fanart entry appears to need to be reported to the LJ Abuse Team before there is any review.
So now that leads to some questions in regards to the community: Should the community require that all fanfics from now on be f-locked if they have the brothers paired together? For fanart, should all art that LJ does not approve of and could report as child pornography to the NCMEC be able to be posted here at all, f-locked or not? I'd appreciate the communities thoughts on this. I'd prefer to hear what people think before I make a decision.