I majored in journalism, I have a fair idea of what it legal and what isn't. I'll check again, but here is my understanding:
Libel is deliberately making false statements for a malicious purpose.
Which means proving libelous actions requires proving: that the statements are false, and that there is a malicious intent behind making them.
As far as information gathering goes: Most civil affairs are fair game, including something like a JC. If they could prove that you violated a confidentiality agreement, then that would probably be grounds for a civil action against you: but I don't recall any such agreement being proposed or signed during my JC's. I'm surprised that they don't make their victims sign such a thing. They are evil enough to do it, thereby squelching most chances at publicizing such information. [It would take a brave and committed exJW to stand up to the horde of dubland's legal barbarians.] But taping a civil or social event to which you are present is absolutely legal as long as you don't commit to NOT taping it.
If the issue at hand is a matter of national security, then gathering and reporting such information would represent a violation of federal law. But of course, JC's don't fall under that category.
CZAR