It's actually the other way around at least for parallel economies. The parallel food market saved a huge part of north Korea from starvation. And the regime knew it and let it slide.

There's parallel market with movies for example.

I'm not saying there are secret societies which freely talk shit about the Kims. But it's also true that parallel societies make significant contribution towards higher quality of life there. Including Russian and Chinese smugglers. Imagine - your business is smuggling stuff to North Korea! Yet there are people for whom this is a good business proposition.