Pretty sure it's not the same (legally) as wiretapping. Wiretapping is specifically described as recording the audio itself without the consent of a party as r

Pretty sure it's not the same (legally) as wiretapping. Wiretapping is specifically described as recording the audio itself without the consent of a party as required by law. If no recording is taking place, I don't think there is any way for it to be considered wiretapping. This is more or less just having a sound meter send an alert when the volume (sound pressure) remains above a threshold for a specified amount of time. As for deducing your behavior - I don't think a court would have an issue with this because I'm pretty sure the AirBnb terms would indicate that such activity is not allowed so taking reasonable measures to ensure that behavior is not taking place would likely be acceptable. Renters/guests do enjoy certain legal privileges that make that space more or less privately owned during their occupancy, but this doesn't necessarily override contractual agreements. Overall, this seems like a reasonable way of ensuring guests don't violate the agreement, provided that there is no recording of audio taking place whatsoever.