It in theory should be true, but the economy is buggered; plus there will always be twats on tourist visas because the Chinese are pretty crap at enforcing laws and often benefit from failing to enforce laws anyway. Also, there will be nationalist pressures to employ more local teachers due to rising unemployment. One only has to look at a recent Global Times article to see that, they talk about parents preferring Chinese only English schools due to all these dodgy foreigners and also a rise in bilingual Taiwanese teachers replacing foreigners.