Seems to be more difficult than leaving the tap on at least.
Further, if people are actually employed and paid, they also pay income taxes. So now the property is even higher cost. Since to pay a person a minimum wage over the year (and the taxes and added costs that gives) is probably more than the property tax for foreigners would have been. Most importantly, the cost of either the property tax or the income tax solution should be higher than any expected gains in the property value (or at least enough to make it useless as an investment).
The best way to game this system would probably be to shadow own it behind some 18year old that has a full time job but lives at home. They have the tax space to make the deduction.
This is easily gamed if Chinese millionaires are truly at fault. They just set up a numbered corporation and "employ" their nephew whose living there.