NEW YORK – The facial-recognition cameras installed near the bounce houses at the Warehouse, an after-school recreation center in Bloomington, Indiana, are aimed low enough to scan the face of every parent, teenager and toddler who walks in.

The center’s director, David Weil, learned earlier this year of the surveillance system from a church newsletter, and within six weeks, he had bought his own, believing it promised a security breakthrough that was both affordable and cutting-edge.

Since last month, the system has logged thousands of visitors’ faces – alongside their names, phone numbers and other personal details – and checked them against a regularly updated blacklist of sex offenders and unwanted guests. The system’s Israeli developer, Face-Six, also promotes it for use in prisons and drones.

“Some parents still think it’s kind of ‘1984,’” said Weil, whose 21-month-old granddaughter is among the scanned. “A lot of people are afraid we’re getting too much information. ... But the biggest thing for us is that we protect our kids.”

An expanding web of largely unknown security contractors is marketing face recognition directly to school and community-center leaders, pitching the technology as an all-seeing shield against school shootings like those at Parkland, Florida, and Santa Fe, Texas.

Although facial recognition remains unproven as a deterrent to school shootings, the specter of classroom violence and companies’ intensifying marketing to local education officials could cement the more than 130,000 public and private schools nationwide as one of America’s premier testing grounds – both for the technology’s abilities and for public acceptance of a new generation of mass surveillance.

The surveillance firms say little about how they designed, tested or safeguarded their facial-recognition systems because, they argue, it is proprietary information. They also play down privacy concerns, despite worries from parents over the lack of oversight into who controls the children’s facial images and how they can be used in the long term.

“We’ve gotten no answers to all these questions: Under what conditions can a kid’s face be put into the system? Does the district need parental consent? Who can do a facial-recognition search?” said Jim Shultz, whose 15-year-old daughter goes to a high school in upstate New York that is paying millions to install a surveillance network offering facial recognition. “It’s as if somebody presented them with a cool new car and they didn’t bother to look under the hood.”

It’s unclear how the systems could have thwarted past attacks, many of which involved shooters who were students allowed on campus. But companies have nevertheless built sales pitches around the promise that campus administrators could block or track undesirable guests – wanted fugitives, problematic parents and expelled students, such as the Parkland suspect – before their violence could begin.

“We were all waiting for something like the Parkland school shooting, for better or for worse,” said Jacob Sniff, the chief executive of Suspect Technologies, a facial-recognition start-up working with a few unidentified universities. “It’s quite clear that a facial-recognition system could have ... prevented it.”

Parents and privacy experts worry, however, that schools are rushing to adopt untested and invasive artificial-intelligence systems with no proof of success.

Andrew Ferguson, a law professor at the University of the District of Columbia, said surveillance companies are preying on the dread of community leaders by selling experimental “security theater” systems that offer only the appearance of safer schools.

“These companies are taking advantage of the genuine fear and almost impotence of parents who want to protect their kids,” he said, “and they’re selling them surveillance technology at a cost that will do very little to protect them.”

No federal law restricts the use of facial-recognition technology, and only Illinois and Texas have passed laws requiring companies to get people’s consent before collecting what the industry calls “faceprints.” That allows local police forces, cities, employers and school boards to largely set their own policies.

Yet, the most advanced facial-recognition systems on the market provide imperfect matches that have been shown to be less accurate for women and people of color, raising concerns that students could be wrongly blocked from campus or misidentified as violent criminals – even from an early age.

The FBI last year said its facial-recognition system, which surveys a far larger database than private companies can offer, has an 85 percent chance of correctly identifying a person from within a group of 50 choices. A Massachusetts Institute of Technology study this year of three leading private systems found IBM’s software correctly identified the gender of darker-skinned women 65 percent of the time.

Children present a unique technical challenge because young faces change quickly and lack the kinds of distinctive features most people develop as they grow up, said Peter Trepp, the chief executive of facial-recognition start-up FaceFirst. But that hurdle has done little to tamp down enthusiasm, Trepp said: Dozens of school districts have expressed interest in his company’s software, which he says can pick a face out of a database of 25 million in less than one second.

Public officials have for years relied on phalanxes of cameras to help keep watch over school grounds. But rapid advances and decreasing prices for facial-recognition technology, fueled by an arms race of surveillance firms eager to dominate the market, have made the systems faster, cheaper and more available than ever.

For schools with high-resolution digital cameras, the companies say, activating face recognition can be as easy as installing new software. One start-up pursuing schools sells a facial-recognition camera for less than $1,000.

Trevor Matz, chief executive of AI (artificial intelligence) video system BriefCam, said there’s been “a seismic shift” in interest in cutting-edge surveillance technology, including from schools.

His company, which was recently bought by camera giant Canon, makes software that can recognize faces and filter video with search terms like “girl in pink” or “man with mustache,” shrinking hours of footage into seconds.

“Everybody we demo the product to immediately goes, ‘Wow’ and says, ‘I want it.’ There’s not a lot of selling that needs to be done.” The city of Springfield, Massachusetts, for example, is beefing up its school security with an additional 1,000 cameras at its roughly 60 public schools in the coming months, all of which will work with BriefCam.

Of privacy issues, Matz added: “I don’t hear them raised. Safety and security trumps those concerns.”

Some school officials say the AI-powered cameras have expanded their crime-fighting abilities. At the 30,000-student University of Calgary in Alberta, security staff members said they used BriefCam to find an arsonist who had set a fire in a campus bathroom with only a few pieces of information, including the direction he was walking and the fact that he was wearing a blue jacket.

Some companies also suggest the possibility of an imminent campus massacre should serve as a call for urgency. In its presentation to companies working with schools, the Israel-based AI firm AnyVision includes pictures and body counts from the Parkland and Sandy Hook shootings, and says its mission is “making sure your children get home safe.”

AnyVision, which says its “tactical surveillance system” can recognize faces and detect guns, offers schools what it calls “anomaly detection” – compiling a historical record of a student’s face, body shape and appearance and pledging to alert security if the student shows up wearing something unusual.

AnyVision chief executive Eylon Etshtein says it’s obvious why schools would want the technology: If a kid arrives one day “wearing all black and carrying a big bag, you’re probably going to want to know what the kid is doing and what’s inside the bag.”

But some experts were skeptical of how well it would work. “Teenagers are anomalies,” said Ferguson, the professor. “Is it suddenly going to be suspicious that a teenager dyed their hair or looks depressed?”

Not all facial-recognition companies are interested in the school-surveillance business, including Kairos, whose clients include Capital One, Ikea and PepsiCo. Chief Executive Brian Brackeen said the technology’s imperfections and racial bias would be “hugely problematic” in trying to stop school shooters and could put innocent kids at risk. “For us, it’s too dangerous,” he said.

Companies able to land a school contract can often reap millions of dollars in public funds. The Lockport City School District in upstate New York recently secured about $2.7 million – or about $597 for each of the district’s 4,600 students – in funding for facial-recognition cameras and other video-surveillance upgrades through the state’s “Smart Schools” bond program, district records show.

Shortly after the shooting at Sandy Hook Elementary School in Connecticut, a New York security consultant named Tony Olivo called Lockport’s superintendent to offer a free surveillance audit, which found that the small district’s cameras were subpar.

On Olivo’s recommendation, the district bought a facial-recognition system made by SN Technologies, an Ontario firm that lists Olivo’s company as a corporate partner and whose top executive said he was “instrumental in the development of our products.” Neither Olivo nor the company would answer whether he had been paid after his Lockport recommendation.

SN Technologies president Cameron Uhren, a former gambling industry consultant who previously worked on casino surveillance, said the company’s AI systems were trained to recognize faces and identify the top 10 guns used in school shootings, including shotguns and AR-15-style rifles.

School district leaders declined to say whether they had sought proposals from other companies before sealing the deal, or how many times they had seen the system in action. Michelle Bradley, the superintendent, said the spending is part of a broad-scale security plan. With schools as top “targets,” she said, “people are on heightened alert all the time.”

It’s unclear how effective the Lockport system would be. The suspects in most of the 221 school shootings since 1999 were enrolled students, a Washington Post database found. Former or expelled students were suspects in about 5 percent of the attacks.

Mark Cuban, the billionaire investor and owner of the Dallas Mavericks, who is backing Suspect Technologies, believes early systems are improving quickly and deserve a place in campus protection. He’s also testing the technology himself: The Mavericks’ locker room features a facial-recognition system that displays calendars and trainer messages for players when they walk inside.

“The concept of school safety will change dramatically,” he said. “While there will be uncomfortable moments with [face recognition] ... based on what we know now, it’s a necessary step.”

Some of the earliest adopters are already looking to expand, including St. Mary’s High School in St. Louis, which in 2014 became one of the first schools in the country to deploy facial-recognition technology on campus.

Cameras in the doorway of the Catholic boys’ school scan each visitor’s face against a blacklist, including parents in custody battles and expelled students. The school now has about 40 cameras, or about one for every eight students, and intends to upgrade its systems this summer to cameras that see better in sunlight and darkness.

“When Parkland happened, I was watching it on the TV going, ‘Boy, I’m glad we have what we have,’” said Mike England, the school’s president. “Some people were saying we would be violating privacy laws, and my answer to all of them is: That’s really not my biggest concern right now. ... I’m going to do whatever I need to do to keep my kids safe.”