> On the other hand, it's just creepy. How do you prevent the next apartment over from spying through your walls? Is the hotel wifi going to recognize and catalog physical activity between two people?

I would imagine you just take the "country/private club" model and extend it out.

e.g. a private club enforces limits on who can access the club and you get more "privacy" since the other people in the club also had to pass through those limits.

In this case, the club/hotel/builder of your house can say "the walls are all Faraday rated so that you get audio, visual and EM privacy when you stay here"