Also, I'm not sure how you'd do a reliable sweep without showing up in person with equipment. Scanning wifi devices isn't necessarily that reliable except for very amateurish spying. The people trying to turn Airbnbs into secret porn studios are not going to be detectable that easily.
I got burned twice (for the same exact period of stay) by two different places on Airbnb, and their customer service was beyond patronising, so I refuse to use them.
(Sorry for the negativity.)
$50 a time for somebody to sweep my room? Nope. If somebody really wants to know what I get up to in a hotel room, more fool them.