It never hurts to be careful.
How to determine if a mirror is 2 way or not
Not to scare you, but to make you aware. This was
passed on by a policewoman who travels all over the
US and gives seminars and techniques for business women.

HOW TO DETECT A 2-WAY MIRROR

When we visit toilets, bathrooms, hotel rooms, changing rooms, etc., how
many of you know for sure that the seemingly ordinary mirror hanging on the
wall is a real mirror, or actually a 2-way mirror (i.e., they can see
you, but you can’t see them)?

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.

So, how do we determine with any amount of certainty what type of mirror we
are looking at? 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 remember, every time you see 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”! This is a really good thing to do.

The reason there is a gap on a real mirror, is because the silver is on the
back of the mirror UNDER the glass. Whereas with a two-way mirror, the
silver is on the surface.