I'd be very surprised if they held a public meeting, charged entrance fees, to... what, annouce something negative? I'm leaning more toward this being simply a way to get fan feedback to know in which direction they want the group's many activities to go. I'll give them points for originality though. In my, admitedly limited, experience with the idol scene I don't remember seeing this.
They probably do the whole array of events: Group Shots and Group Handshakes, the individuals and signs...
Turns out you and mixedmedia were both kinda right. Here's how it went down. Group handshake, group photo, individual handshake/cheki, and finally group photo but by themselves, not with fans. No signing but, you know, who cares?
It cost me 3 of those singles but I finally got my cheki. Happy!