HOW TO DETECT A 2-WAY MIRROR
There have been many cases of people installing 2-way mirrors in female changing rooms. It is very difficult to positively identify the surface by just looking at it. It's time to get paranoid. So, how do we determine with any amount of certainty? Just conduct this simple test:
Place the tip of your fingernail against the reflective surface and if there is a GAP between your fingernail and the image of the nail, then it is a GENUINE mirror. However, if your fingernail DIRECTLY TOUCHES the image of your nail, then BEWARE, for it is a 2-way mirror!
So if not at home and changing before a mirror, do the "fingernail test". It doesn't cost you anything. It is simple to do, and it might save you from getting "visually raped"!
Share this with your girlfriends.
quoted from another website..take note