ilegal Stills
Home distilling was made illegal because of the lucrative tax levied on spirits. The reason given might have been health and safety but money was always the prime mover.
I was under the impression that helium always leaked because it was small and would always find any faults or interstitial cavities. If the graphene layer is a perfect lattice then there are no gaps as proven by its ability to block helium. Water molecules must therefore be 'passed' through the graphene by some sort of active process like a molecular level machine or catalyst.