Those already exist, and not just for the drug trade. For example a bunch of fingernail painting salons recently got raided in my town for that. You don't need

Those already exist, and not just for the drug trade. For example a bunch of fingernail painting salons recently got raided in my town for that. You don't need license conditions for that, though, it's already covered under the law of slavery, minimum wage, immigration, etc.