This is ancient advice for two-way mirrors, IIRC nowadays even legit mirrors can reflect directly from the front instead of the back. In this age of spy cameras this is mostly irrelevant.
Another tip was shining a bright light to illuminate the supposedly dark room on the other side, which again, would be way more expensive than a smoke detector spy camera.
This is ancient advice for two-way mirrors, IIRC nowadays even legit mirrors can reflect directly from the front instead of the back. In this age of spy cameras this is mostly irrelevant.
Another tip was shining a bright light to illuminate the supposedly dark room on the other side, which again, would be way more expensive than a smoke detector spy camera.