My two cents:
If someone has posted something that sounds suss, as Joe said someone should challenge it. If they can't provide a reason or a source for the info (if not an ann or article, at least a rough calculation of an expected price target or profit) rampers generally get aggressive - in that case they violate the rules of the room anyway as I understand them.
Given this forum tends to be a little more high brow than some other sites going (especially the automatic scrolling type forums) I doubt the problem will ever get as bad here as in other sites.