I don't think that's quite true mind. I heard a while ago from someone I trust that there was nothing close. I didn't post his name or owt, and I left out details that would make it obvious where it came from if someone from the club was reading, there were things he told me that were very specific which would likely identify the source. But, having stripped away that stuff, I still posted on the main board the main part of the message (misinformation coming from someone at the club, nothing close at the time, FPP still the most likely rather than just Fuhrman).
Not saying its true, it might have been at the time, things might have moved on, it might even (unlikely) have been wrong from the start. But posting a fairly bland summary of it won't see it traced back to anyone whilst still giving people a bit of info /gossip to take however they wish. I think that is sensible, and I think it happens a fair bit from people who hear a lot more than I do! So I don't think it's right that nothing will ever be shared on an open forum, it's just it'll be more general than you might get in a PM. Even PMs are fairly general mind, because as proved over the road you never know when someone will just cut and paste them. Hard to know who you can trust so it's not worth the risk unless you know the person in real life.
The issue for me, and where it gets annoying, is when people (like Bob) try to be so cryptic that not only does it disguise the source, it also makes it impossible to get even the general gist of the message! Mind, since Bob apparently knows the ultimate sources, I'm not sure why he needs to be cryptic, they know him so they know full well where the info has come from, so he should either post it or they should tell him to stop blabbing on the ****ing Internet!