I wonder, if this is true, since Vienam has a thriving Chinese minority - about their numbers are mostly speculations, but it could be up to two million people!
Oh yes.
Being ethnic Chinese does not mean that you are necessarily loyal to the Chinese regime.
There are considerable Chinese minorities in south east Asia, some are indeed loyal to China itself, other are not.
If you look at Vietnamese history, you will see that Vietnam basically consist of north and south Vietnam, who are not particularly fond of each other, and the people in the interior, who are looked down upon by everybody else.
But there is one thing north and south can agree on: Be vary of the Chinese!
China has for I don't know how long been trying to expand south, along the coast and in all that time been fiercely resisted by the Vietnamese.
Even during the Vietnam War. North Vietnam and Vietcong accepted help from China, but otherwise they were told stay out. That resulted in a medium sized war in the late 70's IIRC, where China was beaten back by the battle-hardened Vietnamese.
China has a major weakness which is becoming evident in these years: They suck at diplomacy. China collects client states (whose heads of states, had this been a few hundred years ago, would have been expected to come to Beijing and kowtow) not allies.
Being allied is like an elephant and a mouse walking along, calling each other "partner" but it is of course obvious who matters the most. It's that pretense that China has neglected.
China has also tried to set up a trade zone in especially south-east Asia. In such a trade zone China would naturally be the biggest and most influential player. But the Philippines, Malaya, Indonesia and Vietnam perhaps also Thailand are not particularly keen on being reduced to subservient client states.
In fact these countries might end up forming their own trading block. Rather than partnering up with a very dominant China. And China doesn't have the same economic leverage as it had only ten years ago.
There is after all a reason why no one, as in no one at all, even USA, wants to know the true value of the Chinese Yuan.
It's really fascinating to study the Chinese economy and foreign policy these years! And it's very difficult to predict what might happen in China in just ten- twenty years from now.