Personally I've never seen photos on here that I would consider over the line. But maybe they have been deleted before I saw them( dam).
I think most of us can have fun without crossing the line. But when we do that there is always the chance the line could be crossed. It's up to You Robin. It's your site and your reputation. You do what you want and if people like it they will follow.....It's worked so far. This is a great place. Use your best judgement. Asking in here if we should have an Adult section is like asking hungry dogs if they would like some steak.
We don't need a seperate room for Adults, What we need is a seperate room for children