There was talk about that earlier in the thread. The best way of doing that would probably to use a Arduino or Raspberry Pi based device. You would create a low power PC basically with a Wifi AP. People connect and can see a web page and/or get documents.
There might be some merits to this but I think it's the law of diminishing returns. A non accessible SSID message is a very simple and safe way of letting people know there are dissenters within the midst. I suspect the majority of curious ones would want to follow a link when there are no other people around.
What would be even more powerful is if at every CA and RC each person awake to TTATT did it. Seeing a handful or more SSIDs when searching for Wifi would be fantastic in my book. I encourage everyone who still has to go to an event to do it.