How can you tell a real mirror?
Conduct A Fingernail Test
One way to check, according to wikiHow, is by conducting a simple “fingernail test.” Place your fingernail against the reflective surface in question. If there's a gap between your nail and the mirror, it's most likely a genuine mirror. How do you tell if a mirror has a camera? Simply touch the mirror with your fingertip—if there isn't a gap between your fingertip and the reflection, it's probably a two-way mirror.