You can tell a regular dream from a lucid just from the fact that you were mentally aware, conscious at some level. You acknowledge that you're in a dream and recognize the implications of that. As for these "fake" lucids, I've had many dreams where I acted like I was aware, but wasn't - my actions were just part of the dream plot, just like flying or non-lucid dream control. These dreams can happen when your mind is on LDing and you think about it a lot.

Anthonyyy0, "fake" lucids don't involve actual lucidity, just acting like you're lucid and without any consciousness.