Let me just say from my experience that if the agent tells you that the building will be completed in 12 mths, you will find that the contract will clearly state that completion is in 18 or 24mths. This is because it may rain, hail, weather is too hot or too cold, etc, therefore delaying construction work. The vendor/developer wants to cover him/herself from being sued by purchasers. The construction company don't want to be sued by the developer either.
It is a legal binding contract!!!
The part in the article that made me laugh was the following:
"There are many risks for developers and purchasers in dealing with property "off the plan".
"If you are considering an off the plan purchase or you have concerns about an existing purchase, please contact us".
Sounds like - It is very risky but talk to us - some of our clients who are property developers are waiting here for you!
A bigger concern on my reading is that a developer, once a sunset clause has lapsed and the development has not been completed, might be quite happy to rescind if the building has appreciated substantially in the 18 months. If you're a developer, why complete on a contract entered into 18 months ago for $300k when the place is now worth $400k and you can sell for a 'discounted' price of $380k?
It emphasises the need to make sure the contract's tight enough to begin with, which is where I think the article was leading.
Of course, if the market goes down between signing and completion then you can expect that the development will, as if by magic, come in on time.