You know how, in dreams, the dream world has extra limitations/bendable rules? In some dreams, you can fly, in others, turn invisible, shoot fire, etc.
How can you tell between if you are actually having a lucid dream, or if the dream world you are in makes you think you are lucid without actually being lucid, AND, is there a difference?
Moved from General Lucidness. 
Well once you relise you are dreaming you are having a LD. I dont think you can think you are lucid without being lucid.n 
It’s hard to explain, but its like this; there is a movie where the plot is about a character who knows he is in a dream. YET, you’re still just the viewer. You cannot control your actions, you are still “not in control”, just like a normal dream. You have all of the abilities of a lucid dreamer within your predecided actions, though.
Has anybody ever had a dream like this, and is the result any different from a normal lucid dream?
I actually asked a professor about this, and they said that there was a fundamental difference, but it shouldn’t really make a major change in the result of the dream vs. if you were actually having a lucid dream. I’m not sure, though, about this answer.
you can tell a false lucid dream from a real ld. if the dream feels like you are a hundread percent lucid, but is in fact just a normal dream then i dont think it would matter, because you wouldnt be having those dreams if you didny practice lding. even if the dream is scripted, and predetermned. you still have the illusion of being fully lucid.
A dream of a dreamer 
I’ve had plenty of dreams before, that in the dream, I say “i’m dreaming” but the level of conscious awareness doesn’t change. It’s still a normal dream, albeit dreaming of a lucid dream perhaps, and doing things I’ve learned I can do in my dreams.
Someone puts 1-10 scales on factors of his dreams, lucidity i think being one of them, which kinda illustrates it nicely. Just like you can be awake in the morning, but still so tired you’re “half-asleep”?
I think the best answer to your question though, is If you really question 
if you’re dreaming, then, at least for that moment of awareness as you realize the dream, you are lucid.
I would not agree with your professor, or maybe he or I misunderstand, but his view sounds like a view I read of the idea that a “lucid dream” was simply an illusion of lucidity, that the dream is still controlled by the subconscious to be played out to the whims of such. I don’t think anyone who has ever actually Experienced a lucid dream can believe that.
I have a bunch of FLD’s.
Have there been threads on this before? Drat. I thought this was a new idea…
Anyways, thanks for the input. I’ve been wondering about this question for awhile…