What kind of mirror does the hotel mean by "this kind of mirror"

This kind of mirror refers to a "two-way glass mirror". Is that you can't see others, others can see your mirror. This kind of mirror exists in reality.

Note: When girls go to public places such as public toilets and dressing rooms, please pay attention to whether the surrounding glass is a real mirror or two-way glass.

Appraisal: Is the "finger method" really effective for the appraisal of this kind of glass? A mirror can see people by reflecting light. However, it is not the glass itself that reflects light, but a thin reflective layer (usually silver, aluminum and other metals). A common mirror is coated with a reflective layer on the back, and the light will be reflected when it hits the back of the glass.

Before the light reflects back, all the illuminated objects will appear in the image in the mirror. If you press your fingertips on the mirror (the front of the glass), your eyes will see a glass with the same thickness behind the mirror, and then an image of your fingers will be displayed. There will be a distance between your finger and the mirror finger, and they won't stick together.

As shown above: stick your finger on the front mirror, and the real finger and the fake finger will stick together. Obviously, this finger detection method is suitable for distinguishing ordinary mirrors from mirrors with reflective front surfaces.

But in a public place like the bathroom, you won't see the kind of mirror that only appears in precision instruments. In these places, if you find your finger stuck on the mirror image, you may encounter a two-way glass with a semi-reflective film stuck on the front of the glass. You should pay attention to protecting your privacy.