A police force has defended its use of facial recognition technology after it was revealed that more than 2,000 people in Cardiff during the 2017 Champions League final were wrongly identified as potential criminals.

South Wales police began trialling the technology in June last year in an attempt to catch more criminals. The cameras scan faces in a crowd and compare them against a database of custody images.

As 170,000 people arrived in the Welsh capital for the football match between Real Madrid and Juventus, 2,470 potential matches were identified.

However, according to data on the force’s website, 92% (2,297) of those were found to be “false positives”.

South Wales police admitted that “no facial recognition system is 100% accurate”, but said the technology had led to more than 450 arrests since its introduction. It also said no one had been arrested after an incorrect match.

As LED streetlights proliferate, they come with the promise of more efficient smart city service. But they also raise new opportunities for surveillance.

Blinking down at passersby in traffic intersections and lining dark alleys, sleek, energy-efficient LED streetlights have begun to replace old-fashioned, glitchy ones. It’s part of a wave of smart city initiatives sweeping the country: Already, LEDs are strung above parts of places like Baltimore, San Diego, Kansas Cityand Bethlehem. Now, Portland, Maine, is in a race with Schenectady and several other cities to become the first to convert their entire light grid.

But as more communities adopt government-funded, eco-friendly LED lights as an environmental measure, some worry that the eyes on these bulbs may be a bit too literal. As they illuminate the streets, they could be watching—and recording—what happens below with attached cameras, microphones, and other devices.