I've heard that said many times without any hard stats behind it. How many absentee purchasers would it take to drive prices up? What about the effects of low interest rates and everyone desiring to get in the market before it gets hotter? Everyone seems to be an expert on this, and I highly doubt that.
Normally a boom in high-end housing is good for local trades (plumbers, electicians, carpenters, painters, decorators, etc) as the first thing most upper-tier home buyers do when they buy a place is renovate, remodel, or at least redecorate.
This has been thoroughly debunked many times. Real estate agents are hiring helicopters filled with asian actors to drive fear. The actual number is something like 3% foreign buyers.
Now, if you look at our mortgage rates - the lowest ever in history with the loosest requirements ever, you'll see why prices have skyrocketed.
We're following the US housing bubble, but about 7 years late.