That other maker I referred to earlier, that is no longer a member here, used to remove, (buff out), the "China" mark on the blades he imported from Guangdong, before selling them as his own handmade customs. And yes, Customs would seize such goods without the proper mark.
When I worked as a special agent in Miami I was called in by inspectors who had seized container loads of Chinese goods, (knives, including switchblades), which were in contravention of customs regulations.
(Not a matter for the unit I worked within, but as a knife guy, they called me down for consultation. The "fraud" group handled those sorts of cases.)