It's always hard to say whether complete prohibition decrease usage or encourage an uncontrolled black market… A possible parallel is that in France the trade

It's always hard to say whether complete prohibition decrease usage or encourage an uncontrolled black market… A possible parallel is that in France the trade of wolf fur is forbidden. There are still a few sellers per month on our equivalent of Craig's list and ebay, but they quickly get taken down by 'vigilantes' reporting them to the website. Not sure about the black market running completely outside of the Internet.