Hi Daniel, fascinating technique!
The only bit I don't get is, what stops you accidentally opening the real box in WL because you think you are dreaming, or, what is to say your inhibition about opening the box remains while dreaming?
Is it just that in a dream your mind opens the box for you, like convincing you that it broke or fell open, and that's the trigger for lucidity?
Worth trying, but knowing my luck I would just not make that link!