Both extended darkness and applying ice cubes are myths made up by people too high to think properly and have absolutely no basis in scientific plant biology facts.
Both these supposed "technique" cause great disruption to a plants metabolism. Any plant that has a deranged metabolism will be under going stress.
A stressed plant can not provide you with the best quality cannabinoids.
Harvesting a plant that is completely normal as she has been for the last few weeks will give you the healthiest flowers, and healthiest flowers will have the best quality cannabinoids/trichomes.
After experimenting with various harvesting times over the last 35+ years, I have satisfied myself as to the best harvest time is about an hour or so after the lights come on/sun comes up.
I believe this is due to the plant being fully recharged after a nights "sleep" with an hour to then get things happening, but before she goes into "defence" mode that occurs after a few hours under the light/sun. This way all the plants functions and systems are at their peak freshness, with fully loaded terpenes and trichomes, resulting in the nicest flowers for harvesting.
Going a day or two in complete darkness and/or freezing the roots is only going to freak a plant out, and any freaked out plant is not going to be at its prime health.
I know which buds I would prefer!
Hope this helps,........
Organoman.