The proposal before members would also mandate that cameras be placed in event halls where they can be clearly seen by attendees. The systems would also need to be freely accessible to local, state and federal law enforcement on demand.

The rules make no mention of safeguards to protect the privacy of event patrons. They would instead require that scanned IDs and video footage from the venues shall be kept for "no less than 15 days" -- meaning, they would be able to keep the information forever.

It would also mandate that all event attendees pass through a metal detector.

"Scanning the ID’s of all attendees at an anti-war rally, a gay night club, or a fundraiser for a civil liberties organization would have a deeply chilling effect on speech," they cautioned in a Monday advisory. "Participants might hesitate to attend such events if their attendance were noted, stored, and made available on request to government authorities.  "This would transform the politically and culturally tolerant environment for which San Francisco is famous into a police state."

The proposal reads like an eerie echo of a warning imparted by Texas Republican state Rep. David Simpson, who told Raw Story last month that he expected a broader push for TSA-like security at football games and on sidewalks.