What makes you "pretty sure"?
Certainly some Chinese have sophisticated methods of exiting money, through overseas corporations and the like. However most Chinese do not, and there are many, many financially unsophisticated rich Chinese.
The evidence is pretty clear that you are wrong. The 20-30% premium Chinese pay for bitcoin, and the inflated Chinese real estate market, both indicate the difficulty. Besides, I lived in China and faced this issue. It is not easy.
Further, Chinese regulators are very smart. The capital controls are there for a reason, and they are effective and enforced.