I don't know about OP, but in Switzerland at least no, that wouldn't be legal for a private citizen to do at their home. The problem is using a camera to monit

I don't know about OP, but in Switzerland at least no, that wouldn't be legal for a private citizen to do at their home. The problem is using a camera to monitor people. It doesn't matter if the camera is only a live video feed to a TV screen, or you save the files to disk, or you run frames through a script without saving to disk. Dash cams are also in practice not allowed for the same reasons (license plates, peoples faces).