Some markets operate completely outside of government control. They have developed their own methods for advertising, product certification, contract enforcement, and resolving disputes. Which of these methods satisfy our ethical principle of Non-Aggression?
People actively involved in outlawed markets will be unlikely to share their information in a public forum. But through academic research, we could learn, for example, how the French Resistance distributed supplies during Nazi occupation, or how businesses adapted to the lifting of regulations after repressive regimes have fallen.
If you are, say, a dentist living under a draconian regime, how can you serve your customers while limiting your risk to State coercion?