This way of working is marketed as such by Chinese manufacturers. They will refer to it as something along the lines of: Made in South East Asia. Sometimes they produce the products in (e.g.) Vietnam, but more often than not, everything is done in China, then shipped to Vietnam for packaging or adding a "Made in Vietnam" label, and shipped out from there. Thailand is another upcoming player in this scheme.
Large companies are well aware of this and happily use their existing Chinese suppliers' SEA entity to avoid sanctions and tarrifs, or to show that they are moving away from having everything Made in China.
To be fair, only gullible or naive people could truly believe that products coming from any part of Asia are not made, controlled, or otherwise influcnced by the Chinese.