Yes, but first I would quickly specify that I didn't say that it was only the U.S. I said that among the laws that we quickly screened, this is all I found for the U.S.
You do have, indeed, a whole variety of set-ups. For example—again, to cite Westminster legislation—in Australia you actually have an opt-in system. The default is that the information is destroyed or is kept confidential and the respondent has to explicitly agree that his or her information would be released after 99 years, I think. Before that, until 2001, the information was completely discarded, actually, after the census in Australia.
But you have other countries in which this is handled differently.
I think in the end it is clear that this is a sort of political decision, an arbitrage, that you as lawmakers will have to make. My understanding is that it does not impinge very much on the functioning of the census itself. I only heard about the experience in Statistics Canada itself when the rules were changed. It didn't seem to have a major impact.