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Hidden cameras in Airbnbs, the stuff that vacation nightmares are made of, are feeding a growing sense of consumer paranoia over surveillance.

Cameras have been found in fake smoke detectors over a bed. In another case, an Airbnb guest allegedly placed a camera inside his host’s bathroom disguised as a cellphone charger. In New Zealand, a bridal party said it found a camera hidden in a lightbulb.

An NBC News review of Airbnb listings in San Francisco found disclosed security cameras in less than 1 percent of rentals.

“There have been more than 400 million guest arrivals in Airbnb listings to date and negative incidents are incredibly rare," Airbnb spokesman Charlie Urbancic told NBC News. "We have strict policies regarding the proper disclosure of security cameras and take reports of any violations extremely seriously. The safety and privacy of our community is our priority.”

Airbnb hosts are allowed to use cameras in "common spaces" like living rooms and kitchens, but not in private spaces. via Airbnb

Concern about Airbnb cameras, widely reflected in social media posts, may be out of proportion to their actual use but they starkly symbolize the loss of privacy that many people feel as security technology proliferates. There are already millions of cameras on public buildings, on streetlights, in cabs and on front porches, and stumbling across one in a rented kitchen only fuels fears that surreptitious surveillance is inescapable anywhere.

Creeping unease

The concerns, like the cameras, are mainstream enough that when Panasonic released a new home security camera integrated into a floor lamp, technology website The Verge cheekily wrote that it “could be in your next Airbnb nightmare.”

There’s even an anti-camera market. Dozens of apps in the Google Play store claim to offer ways to detect hidden cameras. A search on Amazon turns up a variety of devices meant to detect signals from hidden cameras. Technology websites Digital Trends and Lifehacker published how-to guides detailing ways to find hidden cameras in Airbnbs.

Checking your hotel room / AirBnB for those cheap hidden cameras is... — Sara Tasker (@meandorla) January 29, 2019

Airbnb requires hosts who use cameras to disclose their presence in their listings and not put recording devices in private spaces, but some privacy advocates and technology industry commentators have argued that the policy does not go far enough.

David Heinemeier Hansson, founder and chief technical officer of the project management company Basecamp, tweeted it was “bananas” that Airbnb still allowed indoor cameras. “Could you ever imagine staying at a hotel room under 24/7 video surveillance?!” he said.

Caught on camera

It was the business trip booked through Airbnb that got too personal for Paige Blair, a 45-year-old performance coach from Tampa, Florida.

"I turned to leave the kitchen and there was a camera," she told NBC News.

The view from the kitchen camera at the Airbnb where Paige stayed. Courtesy of homeowner

She found not one, but two cameras inside the home she thought she was alone in.

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"Suddenly every little tiny pin hole and every piece of sheet rock looked like a camera to me," said Blair.

Blair reported the cameras to Airbnb and the home owner updated the listing so future renters wouldn't be surprised. She left early and got a refund.

Now she's asking about cameras up-front when she rents.

"You don't know who you're dealing with and frankly Airbnb doesn't know either," she said.

NBC News spoke with the homeowner, Aaron, an information technology professional from Indianapolis, Indiana, who asked that his last name be withheld for privacy reasons.

"I felt bad, I understand how she felt uneasy, being a single female traveling alone," he said.

Citing recent break-ins, he said the cameras are only there for insurance purposes and the footage can't be viewed remotely.

After the incident with Blair, Aaron said Airbnb emailed him encouraging him to relist his property.

Blair’s story echoes recent headlines about hidden cameras in Airbnbs that have gained traction online. Jeffrey Bingham, an associate professor at Carnegie Mellon University, complained after discovering an improperly disclosed camera in the corner of the living room of the Airbnb he was staying in.

“All of us need to think carefully about how we will live in an increasingly surveilled world,” he wrote after receiving an apology and a refund from the company. “Just because it’s so easy to record everything now doesn’t mean we should.”

Security vs privacy trade-offs

The conflict between nosy or wary hosts and privacy-minded renters — for every hidden-camera horror story, there are plenty of Airbnbs getting trashed by partying vacationers — shows how society and Airbnb are struggling to come to grips with the unfettered mass marketing of surveillance.

“A lot of things can go wrong when you’re empowering people who have money and the technical capacity to do something and they have too much time on their hands,” said Laura Norén, a postdoctoral associate at the Center for Data Science at New York University.

Airbnb hosts are allowed to use cameras in "common spaces" like living rooms and kitchens, but not in private spaces. via Airbnb

Airbnb hosts who follow the site’s guidelines on camera use said they make everyone safer and catch rule-breakers. Hosts sometimes take advantage of a new Airbnb feature that lets them mark a checkbox on their listing to note the presence of a security system, just like indicating a hot tub or a “no pets” rule.

Nina Santa Marina, a nonprofit director who rents her “quiet, cozy, cute” three-bedroom home in the Algiers section of New Orleans on Airbnb, goes a step further and includes the warning in a printed rule sheet posted on the guest bedroom wall. She said most guests appreciate the added security.

Those who object are usually the ones she catches trying to sneak in more guests than they paid for.

“What’s the difference between me having them and hotels having them” in the hallway or lobby? she asked. One difference may be expectation. People expect cameras in their hotel lobbies. They don’t tend to expect them in their hotel room.

Ned Mooslin, a 45-year-old contractor from California, wasn’t discouraged by the disclosed external security cameras when he booked an Airbnb for a ski trip with his son.

When he arrived, he was surprised to find there was a security camera in the kitchen. It was for catching guests who didn’t do their dishes, a $25 fee.

“It felt very oppressive, like every move was being watched and recorded,” Mooslin, an experienced Airbnb host, said.

Mooslin said he reported the host afterward to Airbnb. The listing was removed for breaking the disclosure rules.

Check your security settings

Airbnb recommends that guests who have any question about their rental, from where the towels are to how the security system functions, communicate openly with their host and work things out directly.

But privacy advocates say that Airbnb's reliance on disclosures falls short for both homeowners and renters.

"It's not good enough to disclose something in fine print. It's not good enough to disclose something in large print, because the presence of a camera is in itself something dangerous," Jamie Court, president of the nonprofit Consumer Watchdog group, said. "The owner of the home owns that video, what if they catch something funny and decide to put it on world’s greatest bloopers and make a lot of money off embarrassing someone who is in their home?"

Court said he would never stay in a place that had cameras in it, and that Airbnb should rethink its policies.

His consumer advice?

"The minute a camera's in the room and it's disclosed to you, you know that is some form of consent, so you better cover up the camera or get out of the room," Court said.