In the recent news, there are many cases about tenant alert on the bathroom mirror. The target are focused mainly for ladies, so here is a method we can use to prevent from being photographed or video captured. In fact, inside public bathrooms, locker rooms and other public places, we should always aware on this privacy matter. Image source: WikiHow
How to identify/detect the rooms are using looking into mirror?
Online User sums up a method which you can learn from here.
General positive is an ordinary mirror mirror, but from behind the mirror, you can see the Interior! So, girls need to be careful.
To identity whether it is a two way mirror, you can test the mirror with your fingers, if the fingers are not open for two-sided mirror with a gap, it is a normal mirror.
The ordinary mirror: fingers and mirrors between the gaps (normal mirror)
Looking in mirror: no space between the finger and the finger in the mirror (Dangerous, can see through from the other side)