Yup. That's why I think it's just a pretext in order to not look foolish to the overly skeptic and dismissive "public opinion". Debunking might be the group's mantra, but if you talk to individuals, they are mostly quite open-minded. Most of them are really looking for evidence of something paranormal going on. I guess one could call that "undercover" research.
Our groups "publish" mainly in that they have websites with articles, reports, podcasts and videos. I didn't find anything in English, though. Here are some links:
Startseite / News
Paranormal Nord
Ghosthunter Germany | Ghosthunter Deutschland
Paranormal-Saar.de
Paranormal-West-Ghosthunter • Paranormal-West-Ghosthunter
I guess from the fact that the last updates on some of these sites seem to date back to 2011 one could deduce that the ghosthunter "hype" is already dying down (none of this is really considered to be of any significance officially, so this movement has never been too visible either, only in interested circles). Although there are investigators who are really doing it with scientific interest, there are a lot of "hipsters" involved who have already turned to some other trend.
A while ago I was registered on one of their forums but there was so much in-fighting going on between groups and often arguments between skeptics and believers in the same group, that I quit real fast. I chatted and posted with some very credible guys that had had really incredible own experiences and thus were very inclined towards paranormal theories, but their arguments were mostly subdued by skeptics who hadn't experienced anything themselves but who knew exactly that it was all infrasound, pareidolia etc.
@goggs: thinking about that time on the forum there, I remembered chatting with an alleged "experiencer" who I judged by his posts and chatting to be quite intelligent, non-deceptive and down-to-earth. He related something that reminds me of your story of the old lady seemingly disappearing.
He typed that he had been staying over night with a friend who had moved into the apartment some months before. In the morning, he entered the bathroom and there was an old woman just standing there. He quickly said sorry and left, assuming that the friend's grandmother was visiting or something. He didn't notice anything unusal about her appearance, but of course he had only seen her for a split second. When he later asked where the old woman had gone to, his friend assured him that there was no one in the apartment except for the two of them. He (the friend) made jokes about there being a ghost in his apartment, because although he himself had never seen anything, several guests who had been staying there overnight, had reported seeing an old woman, too.
Of course, just another anecdote and not very convincing, I guess. But still.