This depends - see the alchohol prohibition, if there's a large enough market and the product is easy enough to make then banning the product just creates an un

This depends - see the alchohol prohibition, if there's a large enough market and the product is easy enough to make then banning the product just creates an unregulated black market. Which can create more problems if there's tainted products being sold, legal users will have to avoid otherwise legitimate shops that have at least _some_ degree of liability vs some random friend of a friend who has "good stuff" - who has no incentive at all to care about health or safety.