Hey dreamviews!

Okay, so whenever I try to explain lucid dreaming to other people, they will almost always at one point or another ask the same question:

"But what if you one day think that you are dreaming when you are actually awake and throw yourself off a cliff or something?"

Now, I have never heard of anything like this happening (outside of Inception, I mean), and I would like to think that it cannot happen - but I don't actually have any proof for it, other than "Well, you can fool yourself into thinking that are awake when you're dreaming, but it doesn't really work the other way around".

So, does anyone know of any solid evidence against this, or could it in fact theoretically happen?