Repugnant markets and black markets -- interview

Here's a short interview on repugnant markets, in Stanford's engineering magazine:

Repugnant markets spur thinking about how to engineer complex systems
"​When some people want to engage in economic activity that others seek to ban, society faces tough choices in designing the right market incentives — or disincentives."
By ​Edmund L. Andrews

"when is it effective to outlaw an activity, and when does that simply foster a black market? At what point does it make more sense to focus on harm reduction than prevention?

"Roth expanded on these ideas in a recent interview..."

Another link is here.