Suppose you advertised for a party at a specific time and place, but didn't associate yourself or anyone else as the organizer. When people show up, there's no leader. No instructions. Just a bunch of people who heard there was a party (or however you want to advertise it). This is sort of a bee hive, except that nobody knows they're in a bee hive.
Nobody can know who advertised it, and it's probably best if you don't attend either, so that you don't let it slip what's going on. If you can hiddenly observe it, that'd be great. It'd also be cool to find out about it by talking to folks. "Hey, did you go to that party the other day? I wanted to, but had a meeting. What was it like? What happened, the fliers didn't really say. Who was there? Did you like it?"
This is sort of like Critical Mass
and public 4:20
gatherings, but without a purpose. Those are recurring events that started by a group of people spreading the word and participating, and they grew on their own. This is a one-time event where the promoter isn't involved and there isn't an obvious task upon arrival.
If you try this out, let me know.