Great article. And as a fellow british Lolicon, I say keep your nose clean, your head down, and don't give them any reason to pick on you. Generally, its an open secret that despite having near unlimited powers, our crime prevention/detection services are stretched to breaking point. Unless something is brought directly to their attention, or is an ancillary crime to something else- e.g, you're a drug dealer or terrorist- thought crimes and paper crimes are a very low priority for them.
Is there a chance you could, like that one guy, still get arrested? Perhaps, but if you know your rights, keep a cool head, you can probably cut a deal. Most Police officers would rather be dealing with real criminals, not wasting time going after you specifically.
Its good to be paranoid, but be realistic about it too.