Funnily enough, this is how reflections are usually emulated in game engines that do not support raytracing: another copy of the world behind the mirror. Also used in films in a few places (e.g. Terminator)
Please look at the refrigerator I mentioned—it's definitely not the classic "mirror world" reflection that you'd normally see in video games. I'm talking about the specular / metallic highlights on the fridge being simulated entirely with depth features.
