Individuals cling to their faith and you can't alter their views, particularly without any supporting research. Freezing isn't necessary for short periods, and even long-term needs are questionable. There's footage of someone who misplaced a substantial quantity of that substance in a storage area for a decade, only to find it remained fully effective upon testing.
Many discussions mention folks placing their powder forms inside special protective boxes before putting them into cold storage. I'm wondering what real benefit that offers compared to just placing the packages straight into the cold unit. With everything properly sealed shut I doubt moisture would cause any problems. When I searched around various threads the huge number of references to low temperatures made it impossible to find any relevant details.