There's no reason to assume that China's tech actually works in the field.
In totalitarian china, everyone is a suspect, so detecting a suspect is trivial.
That article does a decent job of explaining that the surveillence is as much pseudoscience and propaganda as scientific technology.
>>>>
China’s national database of individuals it has flagged for watching — including suspected terrorists, criminals, drug traffickers, political activists and others — includes 20 million to 30 million people, said one technology executive who works closely with the government.
...
Officials said humans still sift through the images to match them to people’s identities.
...
In Zhengzhou, police were happy to explain how just the thought of the facial recognition glasses could get criminals to confess.
Mr. Shan, the Zhengzhou railway station deputy police chief, cited the time his department grabbed a heroin smuggler. While questioning the suspect, Mr. Shan said, police pulled out the glasses and told the man that what he said didn’t matter. The glasses could give them all the information they needed.
“Because he was afraid of being found out by the advanced technology, he confessed,” said Mr. Shan, adding that the suspect had swallowed 60 small packs of heroin.