Years ago I was on a ride organised openly on CC. This included the nominated cafe stop. When we got to the cafe stop someone accosted one of the riders (not me!!!) and rather loudly and dramatically accused them of something (having an affair ... something like that). All very loud and unpleasant. The accuser knew where the accusee would be from CC. IIRC the two had not met before in real life, so there was some stalking going on.
All kinds of things can happen which is why I personally think it's best to organise such things on private chats and use the open forum to ask for interest. Then people can be added/removed from the chat and details are not out in the open, and people can say things like "You'll recognise me because I'm riding a Pinarello Dogma diamond-studded special edition with gold-plated DI2, that I never lock for fear of scratching it". I'm normally shy about letting people know that I have such a cool bike.
It's a minor hassle setting up the chat, but once you're on it's just as easy to reply to/monitor as a thread is.
Just my 5p.
Gold-plated Di2?! Maybe for a pub bike.