When a non-resident buys a property to rent out, how is the rental income taxed?  When they sell that non-principle residence how is the taxable capital gain collected?  I suspect it is not.  If CRA suspects that investing in, and flipping properties is a business and not an investment in the normal sense, they can classify it as income and not capital gains, but they don't do that either!
My point is we already have he tools to dampen speculative buying, but neglect by our government has given rise to these other foolish and redundant options.  When a property is sold by a non-resident, there should be a significant withholding tax of percent of the proceeds until the CRA is satisfied that all applicable taxes have been paid!   Also, the Real Estate board dos not have a clue who is buying homes.  Recently a neighbour sold their property and believed a "nice" family bought it and were moving in. The home was actually rented out and is currently occupied by foreign students!