Hong Kong born Canadians do not need China Visa to China? How about China born Canadians?

What is the effective date? Any firm confirmation? I did the 72 hours to Shanghai in June, 2013, most of the airlines do not know about it, they looked for transit G in my Canadian passport for hours and kept on calling for information. We almost missed the flight

How to confirm the new policy? The Chinese Embassy phone line is always busy busy busy.