The government has directed Statistics Canada to look at even more options for changing the Census in subsequent iterations. Since they have broken the important continuity of the data systems, this probably makes sense.
The use of registration data is one of the options discussed for future changes to the Census. Of course, in a CP story, Jennifer Ditchburn correctly pointed out that we don't have mandatory registration by place of residence and we do not require significant locational and demographic information from all of our residents. The use of identity cards and mandatory registration does not scare me personally. Most of the people who would object to such things probably provide more information to their retailers or other loyalty card systems. Statistics Canada has made innovative use of administrative data and should be encouraged to continue to do so. Additional information can always be used to improve quality and timeliness.
My biggest fear with such data is that we have too many jurisdictions who insist on managing such systems themselves. Trying to sort out 14 jurisdictional games will just increase costs and lower quality. To many of our health care datasets are forced to exclude Quebec because of issues of integration and control of administrative data systems.
Mention is often made of the US use of an post-censal survey. It should be noted that the U.S, found that this must be mandatory to get an adequate response rate.