There are large numbers of refugees from Mainland China, but you just don't hear about them, especially here in Taiwan. Mostly because it is a very profitable human trafficking business, backed by "government" officials on many countries.
You wil hear about in Central America for example when every few months or so a boat capsizes with 600 or so many souls on board. That rarely makes the international news, not even a CNN prompter. You see, larger numbers, up to several thousand of Chinese, are crammed in fishing boats, taken to Central or South America, and then work in indentured slavery there until they have enough to pay off their debt to the snakeheads in China and the coyotes that will take them on the great hike across the Rio Grande. The great goal is making it to the US, not Taiwan.
In Taiwan, well, we have the hero celebrations when the soldiers surrendered in Korea after the war and came to the Island. Mostly because of the still ongoing war, in later decades, any pang or raft where people would try to come, would be shot on sight... if it even made it out to sea. The Taiwan Strait is a trecherous killing machine of rough seas. No Mediterranean calm. And even the inner sea has taken so many lives...
With relations so "good" and "close" now, of course any boat people nowadays would be sent back, as they would symbolize an embarrasment to the Motherland. Here, they would argue illegal immigrants and unfair competitive cheap workers and so and so.
Now, we do have large numbers of Mainland women being sold or selling themselves in sexual trade in Taiwan, but as other posters have said, there are other opportunities for economic advance in their own land-like, being the mistress of a rich guy in one of the many mistress cities with fancy apartments set in the periphery of the larger citadels, for example. Or they marry legally, say, an abei of 80 or 90 who yearsn for a taste of the Mainland...
The worker trade is big business, managed by cartels who feed up governments. They are a tool of social stability, you see, giving people the illusion that they are actually doing something for their families by sending money home. Hence, the cartel of South East Asia would be trading Mainland workers -and it will- if it can do so with great profit and larger impunity.
Economic refugees make the largest number. If you are a political refugee, you won't make it out of China alive and then come to Taiwan. Too close for comfort. Just take a look at the ones that did make it out from Tiannamen and what became of them. Happy campers they ain't.