It's not. Chinese converting shipping containers to hide weapons/troops has been open knowledge for some time now. I heard about it years ago but have seen articles quite recently. Here is an example, and it's not from the lady who did the translation. It's from the Naval War College:
https://digital-commons.usnwc.edu/ils/vol97/iss1/45/
Whatever. If you think the Chinese are on the verge of invading the mainland US via soldiers in shipping containers, be my guest. My opinion is the CCP doesn’t think they need to invade us. They’ve already got us by the sneakers. The Chinese wisely tend to take the long view.