This has been proven to be a rumor long time ago. Canadians can still stay in the State for 90 days (or 180 days, I am not sure) without visa.
I don't know whether the rumor has been spread out deliberately or just by mistake. The actual situation is: Originally, those Canadian permanent resident who originates from British Common Wealth countries don't have to apply visa when going to the States for a short trip, but now, all of the them except six countries(I just remember Singapore) have to apply visa. Then, on some Chinese websites, the Canadian Permanent Resident has been modified to "Canadian citizens". Just a rumor, my friend went to the States with his passport the day before yesterday to see his elder sister.