I'll try to be fair here.
We can't make it immediately. I need.. At least 3 votes from our members (Marto, Sorrow, CVfan13 and I don't count since we're the ones who are going to decide it in the end anyway >_> ) if we're going to open that subforum or not. I'll make a thread where people can cast their vote. I don't think Guests should be allowed to view it though, and they shouldn't by any means join up BECAUSE of it. >.< It's unlikely, but it's possible. If ever, think I'll have to require regular members to have at least 3 posts in other subforums before they can view the "R18" section.
Hmm. Also, there's the problem of who's going to moderate it.