Law of Economics

The One "Law" of Economics
I have read a great deal of economic theory for over 50 years now but have found only one eonomic "law" to which I can find NO exceptions:

Where the State prevets a free market, by banning any form of goods or services, consumer demand will create a black market for those goods or services, at vastly higher prices.

Can YOU think of a single exception to this law?

taken from: Email to the universe by Robert Anton Wilson