Traditionally, the Fourth Wall refers to the fourth, imaginary/invisible wall separating actors on a stage from the audience. According to wiki, it's a concept that's been around basically since forever, and seeing as (slash) fandom in general is a largely literary space, the concept's been adopted here too. We have adapted the meaning to fit our context - in fandom in general, fourth wall expresses the mindset of making a distinction between canon/source material and fanon, of drawing a clear line and putting an invisible wall between fan-created materia and authors/screenbook writers/actors/musicians.
Some authors such as J.K.Rowling very openly encourage fanfiction - in general - and have kept companies (such as Warner, in this case) from pursuing fanfiction writers, but that's really just the exception to the rule that authors don't like their material being used in fanfiction.
And that's just
written material - how about when it comes to personal rights? Bandom is a RPF fandom as much as any actor/celeb-based fandom even though we like to pretend it is not. We like seeing the shows and listen to the music and somewhere in between there we form a picture of the boys and girls in our heads that might be close to reality, but not so much that we are acutely aware of it. The fact that those boys and girls
are real seems to elude us more often than not.
Yes, they live a very public life, they love and marry and break up in the open, most of them do, and Pete Wentz likes encouraging his fans, but don't they have a right for privacy, a right
not to be confronted with activities by their fans that they might not find appealing?
We're dancing on a very fine line with bandom - both on a legal and on a personal level - and I feel some people have yet to develop a sense of tact in this regard. Even if you say that you would be comfortable with having fanfiction written about you and have people come up to you to tell you about it, hand you weird signs, even if you're ok with that, it doesn't mean that those boys and girls in the bands are.
Are they encouraging it? Yes, some of them are, but only up to a certain level and we should never, in personal contact with them, go further than they are going. They're in this for the music and I don't think we have a right to push them any further than that.
The fact that they don't openly protest against this when confronted with fandom - albeit, Panic, at least, has expressed their dislike in interviews before - doesn't mean that they approve, encourage or even agree. It just means that they're not lacking the sense of politeness and tact that some fans seem to be missing.
And apart from that - remember, legal gray area. Pushing our possibly illegal writings, communities and rpgs in their faces is not going to make it any more legal.