It takes weeks for the plant to produce resins, which to my understanding are a byproduct of the plant protecting itself from light intensity and pests ..like sunscreen with deet. So, take away the sun (light), and the plant has no reason to "protect" itself or produce more resins.
And, don't trichomes take weeks to ripen as well? So if you have a final 48 or 72-hr push for trichomes, theoretically wouldn't they just be new, clear heads?
I dunno, the whole dark period sounds like pseudoscience to me.