Yeah, it's a losing battle. You cannot prevent what happens in shadows and secrecy without bearing enormous expense, restricting the rights of your citizens, or both. It is a losing battle, and one that we would all likely be best served by allowing it to happen. Spend resources to protect honest citizens from being affected by that activity. Use resources to dictate where and when it happens. Limit its effect on those who don't participate, don't spend money trying to prevent it from happening.