https://www.restsensor.com/ is the new name for https://noiseaware.com. They got started making a 'noisy party' sensor that is monitoring the audio in your hotel room or AirBNB. You can see the Noiseaware branding on the sensor in that X thread.

So it's not just a $500 scam, it's also a privacy issue. I had no idea these audio sensors were even a thing.