A hidden camera or even a visible one changes human behavior. Domestic workers, babysitters, and overnight guests act differently when they know they are being recorded. While some argue this encourages "good behavior," others see it as a violation of the reasonable expectation of privacy inside a private residence.

Modern systems (Unifi, Reolink, Hikvision) now offer . This allows the camera to record , but black out specific zones in the frame. You can mask out a neighbor's window or your own bedroom window. The camera sees the intruder in the yard but software deletes the pixels over the sensitive area.