Came across this FOIA request regarding a festival that was held last year in England.
Apparently the idea was to place cameras around the festival area, and to capture images of the 100,000 festival goers and the. match against a subset of known festival criminals / cell phone theives.
No matches, or at least no arrests or evicitions resulted from the system, although the control cops were picked up 77 times.
People weren't told ahead of time that their picture was to be used in an automated face rec system.
Some gratuitous detail supplied by the authorities:
This works by scanning faces passing CCTV cameras and comparing each one against a watchlist. Each facial image is immediately compared against the watchlist and if not matched, the image is removed from the system. However, if a person of interest is identified, NeoFace Watch immediately sends alerts to officers and staff. The potentially matched images were only retained for the duration of the festival.
Intelligence officers drew together a database of offenders from across Europe who were known by the police to target large music festivals to commit crime. Their images were enrolled into the NeoFace Watch system, provided by NEC. This was a standalone system located within the festival grounds and not connected in any way to any external system.
Six cameras were placed in a small area of the site at Donington Park, for some of the festival, and scanned the faces of festival goers. At no point during Download were unmatched facial images retained by the system. Because it was a controlled trial, a number of officers and staff volunteered to have their photograph enrolled into the database and they were successfully picked out 77 times.
No one was arrested or evicted from the site as a result of the NeoFace software. The database of offenders and potential matches was permanently deleted at the end of the event.
Related: 18 Million Face Database Now Operating In The U.K.