If we look at this from a scientific standpoint it seems logical to use a 24+ hour dark cycle to initiate flowering.
The plant uses a number of protein pigments to, more or less, tell time. These pigments absorb photons (light) and take on an excited state, where they do a number of things. During a day period the pigments will remain in this excited state. During the dark cycle, the pigments are able to relax from their excited states. They now can interact with proteins involved in flowering and stimulate the production of flowering hormones.
So, breaking it down a little further, these pigments are like a key. A key that only works in the dark. The key unlocks flowering. The longer the key is around, the longer the door to flowering is open.
So, if you hit the plant with an excess of dark it will build up large concentrations of proteins and hormones necessary for flowering. This should kick-start the flowering process, which is cool.
I honestly believe that there must be some way to flower in absolute dark.