I predict mass real estate sell off in every major city around the world. Millenials world wide collectively let's out a sigh of relief.
Why though? What would the wealthy Chinese people that own it want to do with the cash instead? I would think having your investments in a stable country instead of one in chaos would be ideal?
It is possible that some may feel the need to become liquid in short order, but I think that most are going to be smarter and follow your thinking. Owning real estate outside of China gives them an asset that is relatively safe from being seized and which can help fund a flight to safety if it ever comes down to a 'blood on the streets' scenario.
How many of those wealthy Chinese - never mind non-Chinese banks and investors - own property clear, and haven't leveraged it to "re-invest" it?
remember tiananmen? couple thousand people run over by tanks is a price worth paying for that government.