Ok, results from night 1 of trying this: no lucid dream, but great recall. And I was definitely headed towards a lucid dream, but unfortunately at some point in the night the cardboard got bent up and stopped touching my hand, and that's also when I stopped having great recall and stopped heading for lucidity, so I think that pretty much proves this isn't a placebo...cuz how was I to know the cardboard got bent up when I was totally asleep and in a dream?

I'll try a different setup and see how it goes. I move quite a bit in my sleep, so I need the cardboard to be really securely in place.