The important thing is not the direct effects of the tax itself, it is the effect that this may have on the story that locals are telling themselves about Vancouver RE.
From what I informally overhear, many people are talking about the effects of this tax.
If enough people believe that this will lead to dropping prices, drops will occur.
Local owners intending to sell will hurry to realize paper gains; Local prospective buyers will evaporate (see Spot the Speculator).
Speculators abhor falling prices.
Momentum speculators (off-shore and local) will withdraw.
Locals intending to buy far, far above wage or rent determined fundamental values will stay away if they can no longer be ‘certain’ of future price gains.
A market like Vancouver RE circa 2016 (25% gains in the last year!!) is dependent on ever rising prices to suck in new buyers.
Once it is seen, or believed, that Vancouver RE prices can drop substantially, at what level will prices stop falling?
[50% of uber-astronomically-overvalued is still substantially over-priced.]