There was a recent story in the Vancouver Sun of a buyer who purchased a pre-sale condo in the Trump Tower and put down her first deposit payment of $275,000.
For whatever reason prior to the second deposit being due, the buyer decided they did not want to go thru with the purchase and decided to not pay the second deposit. This was a critical mistake! By doing this she was in breach of the contract and immediately forfeited the deposit. She should have consulted a lawyer who would have explained her legal liabilities and her options.
The lesson to be learned is never buy a pre-sale unit directly from the developer. Always use a Realtor who will give you fiduciary duty and legally represent you in the transaction. Remember, once you have a firm contract in place to purchase a home there is no going back. If you cannot complete for any reason your deposit funds will be lost and you could also get sued for damages by the seller.