Here's the biggest consequence of Hong Kong's property curbs

Supply of secondary market properties was squeezed further.

According to Colliers International, the unintended outcomes arising from the government’s intervention is the further squeeze in supply of secondary market properties as owner occupiers are unwilling to sell their homes at substantial discounts; on the other hand the crowding pent-up end-user demand for mass properties makes it harder for first time home buyers to enter the market.

Here's more from Colliers:

The slower than expected economic growth in mainland China and increased concerns about the US Federal Reserve moving closer to reducing its stimulus package, prompted companies to remain cautious in hiring.

Leasing demand remained subdued during 2Q 2013, especially the top-end of the market. however, demand for mid-to-low end properties remained intact, continued to be supported by tenant downgrading and demand from the non-financial sector.