I remember reading about that, Bobblehat. It really does seem like it should work but there are a few reasons why I don't like using emotions for this technique. The big one I see is that for most people, we go about the day generally on neutral. Those more "extreme" emotions(excitement, sadness, ect.) in which you would use a RC are much more rare to come by in a typical day, although they are abundant in the dream world. This makes using emotions to trigger lucid dreams more difficult to practice in reality. Also, when you do feel that intense emotion, the emotion itself interferes with your ability to logically say "Ok, I am feeling excited, time to do a RC". Those emotions are hard to come by, so your mind is more preoccupied with the experience of that emotion. However, the activities used in CILD are ones that occur so often it's routine, freeing your mind up to think "Ok, I'm talking with Joe, become more aware"