You are projecting the Chinese government's ability to monitor a company's illicit activities. If that was the case, there would be no corporate crimes, at least the major ones. Never underestimate a white collar individual's ability to camouflage his shenanigans.
Um, no let’s be very clear here, ZTE has only violated domestic US sanctions. There was no UN sanction or international law broken.
The US domestic laws would have as much international standing as a new Chinese law criminalising business dealings with Taiwan for example.
China could pass a law tomorrow to sanction any western firm that does any business with Taiwan, SK, Japan or any other country that catches its ire, would that make it ‘illicit’ for western companies to continue doing business with those countries?
What America is doing with ZTE, and threatening to do more broadly with its impending threatened withdraw from the Iran deal, is leverage its market position and power to force other countries to follow its own domestic dictats.