(KDVR/WGHP) — Airbnb leaped into Twitter’s Trending page, and the reason may be cause for concern.

Twitter user @howietrbl wrote Monday:

girlies that use airbnb, download the app “fing”. It shows you everything in the home ur in that is connected to the wifi :) it helped my friends and i realize our host was recording our sound levels in secret to try and charge us extra lol. Also shows cameras in the home!”

The tweet, which was shared more than 24,000 times and liked more than 141,000 times, sparked renewed concern over hidden cameras in rental homes and hotels.

Howie added that, while the app may not be perfectly accurate all the time, “it helped me so I shared it to potentially help anyone else.”

It can be easy for Airbnb hosts and hotels to hide surveillance cameras in their properties without guests knowing. We’ve reported plenty of previous cases of exactly that.

So here are some tips for investigating your room or rental.

Back in September, we spoke with Thomas Ham, the owner of Spy Catchers LLC, a professional technical surveillance countermeasures company. In a viral TikTok video, Ham showed viewers how easy it is for Airbnb hosts and hotels to hide surveillance cameras on their property without you, the guest, knowing.

So what is Fing?

Some experts also suggest downloading the free smartphone app, “Fing.” The app is available on the Google Play store and the Apple App Store.

“The ‘Fing App’ works if you have the WiFi password for the space you’re staying at. It will log on to that network and it will actually give you a listing of all the devices currently listed on that network. It tries its best to give you an idea of what each device is. Whether it’s a cellphone IP, cameras, things of that nature,” said Ham.

How to spot the reflection

Guests who are staying at an Airbnb or a hotel can easily find any recording devices (if there are any), by shining a light into a hidden camera lens.

Experts, including Ham, say the camera lenses will reflect a blue or red color when hit with light.

The typical areas you should search include such devices as an alarm clock, smoke detector or shower head.

Turn off the WiFi, find a red flag

Ham offered another tip: When you first enter a rental property, turn off the WiFi and router.

If you get a call from the host letting you know the WiFi has been turned off, that could serve as a good segue to bring up a conversation about whether there are any cameras on the property.

Airbnb’s rules about hidden recording devices

Airbnb has rules in place to protect its guests from any hidden recording devices, which it defines as “any mechanism that can be used to capture or transmit audio, video, or still images.”

On its website and in its app it lists the following:

Our Standards & Expectations require that all members of the Airbnb community respect each other’s privacy. More specifically, we require hosts to disclose all security cameras and other recording devices in their listings, and we prohibit any security cameras and other recording devices that are in or that observe the interior of certain private spaces (such as bedrooms and bathrooms), regardless of whether they’ve been disclosed. Intentionally concealed recording devices (such as hidden security cameras) are never permitted.

Rules for hosts: 
If you’re a host and you have any type of security camera and/or other recording device in or around a listing, even if it’s not turned on or hooked up, we require that you indicate its presence in the Things to know section under Health & safety. We also require you to disclose how guests will be monitored and if an active recording is taking place. If a host discloses the device after booking, Airbnb will allow the guest to cancel the reservation and receive a refund. Host cancellation penalties may apply. Find out how to disclose info about security cameras and recording devices. Different rules apply for listings in mainland China.

Rules for guests:
If you’re a guest, our Standards & Expectations require that you not spy on other people, or otherwise violate others’ privacy. Our policy prohibits the use of a security camera or any other recording device by a guest to monitor a host or any third party present in the listing without the consent of that person. We encourage you to discuss the use of security cameras and other recording devices by using Airbnb’s messaging feature.

Violating this policy may result in your suspension or removal from the Airbnb community. In addition, you should ensure that your use of security cameras and other recording devices is consistent with applicable local laws and regulations.

What’s considered a security camera or a recording device

Any mechanism that can be used to capture or transmit audio, video, or still images is subject to these rules. This includes, but is not limited to, things like Wi-Fi cameras (for example, Nest Cam or Dropcam), nanny cameras, web cameras in computer monitors, baby monitors, mounted or installed surveillance systems, decibel and device monitors, and smart phones with video and/or audio recording capabilities.