Fact Check: This Test Of Hotel Mirror Does NOT Conclusively Demonstrate If It Is 2-Way Mirror

Does this video show a reliable test to determine if a hotel mirror is a standard mirror or if it is "fake"? No, that's not true: The test shown, frequently done with a finger and called "the fingernail test," is not a foolproof way to tell if a mirror might be a two-way mirror, which would enable a person or camera on the other side of the glass to see in the room. The test in the video is a reliable way to tell if a reflective surface is on the front or back surface of the glass, but this alone does not conclusively determine if this is a standard mirror or a two-way mirror.