You should be worried when the CEO of Beijing's largest real estate company Zhang Xin has this to say:

My view is that the real estate business has a lot of asset bubbles, but even with asset bubbles it doesn't mean that we are getting out of the business. The strategy is not giving up or leaving, the strategy is to keep a lot of cash, to sell as fast as possible, and to turn around assets faster – even faster than before.
She points out that rent is way too low for the prices at which properties are selling:
Now, if you look at the prices for the property being sold versus the rent you collect there is a real disconnect. Prices are too high, rent is too low, so if you hold property in order to get yield you are likely to get very little. For us it makes no sense to hold property, so our strategy is to sell everything. We see ourselves very much as a manufacturer. We buy land, we build, and then we sell. And the asset bubble has compelled us to be even more of a manufacturer.
If property developers who are interested in long-term income streams won't even consider holding on to their own properties...should you?

Read the whole interview for more of her thoughts! Thanks to Twitter Niubi for pointing this interview out!