I think I agree with your position. If I invite someone to be a house guest for a month and “make themselves at home”, they would expect (and I would have reasonably given) a certain expectation of privacy, which they could use to fulfill certain bodily needs. This expectation includes not being recorded. An inspector or other service provider, or even a birthday party guest wouldn’t be granted this same expectation of privacy.
Hidden cameras are a thorny matter, especially when it involves consensual intimate acts without one (or more, or all) party knowing they are being recorded. And I wholeheartedly believe that making a recording of intimate acts without the express consent of all parties should be illegal. This, however, does not seem to be one of those cases.
