I think this is in reference to the $500 daily limit for foreigners transferining RMB out of China. If you try go to a bank and try and wire money home, anything more than $500 requires a tax certificate, your contract, and your residence permit, and even then there are hard limits based on your income. A couple of years ago I did a favor for a friend who was leaving, his employer promised to transfer his final paycheck to his home country’s bank account, and they broke that promise. I transferred it out for him, and ended up being rejected the next time I tried to transfer money to my home bank account.