How do you even know a buyer  is "foreign"?  The Chinese demographic comprises about 65% of Richmond, that's citizens or residents living and/or working here already.

Since when is asking your estate agent for the nationality of a buyer, and then their citizenship status,  an acceptable thing? 

Answer:  It's not.

The reality is, a good portion of the house buying that you think is "foreign" are actually new residents and citizens buying via overseas earned/sourced money. And like every other Canadian citizen,   they have every right to do so.