It's good this item is in the open now. 

Flippers pay an assignment fee to the developer but they do not know the new purchase price, and on closing,  the property is sold at the original price to the new purchaser. Lenders will provide mortgage/loan only on the original price and the gap has to be bridged with own funds. That means only the cash rich new buyer can close the  transaction.

Taxman looses as well on the gain made by the flipper and in the land transfer tax that is levied on the original transfer price. Non-residents must be made to pay the non-resident tax to the ministry when making the initial agreement, and then the ministry will be able to tract the progress. 

Housing market distorts everything in the economy. Governments have a duty to protect its citizens/residents. Assignments must be limited to  special situation only.