In the 2001 census—and it was all compulsory then, I guess—but in the compulsory short form, 20,000 Canadians identified themselves as Jedis. When the question was asked what their religion is, they said they support the Jedi religion. In other words, they've watched too many Star Wars movies.
The idea that you can get accurate information by compulsion has no support that I am aware of anywhere in the literature. What you can guarantee by compulsion is a response. You put a gun to somebody's head and that person is going to say something. It's almost like the argument for waterboarding. If you waterboard enough people, they'll tell you something. The question is, are they telling you something that is reliable and usable, and what damage have you done to their sense of trust in their government, particularly if the information you're asking for goes very close to their sense of private domain?
I don't think there's any inconsistency in using fines, and even prison, when the information is of the most fundamental sort and when we can all clearly see that it does not go to one's internal privacy. Needing to know where someone lives, what their language is, what their address is, or how many kids they have is in the public domain. If someone is not prepared to answer that information, then I think they are showing you a degree of contempt for society that justifies some additional measures.
But when you want to sit down and question someone about whether they have mental illness, or what their child-rearing habits are, or how much money they have in their bank account and what their pension is going to be that they've worked for, and when the person who's asking you that question is quite possibly a volunteer from down the street, I think you're going to get a lot of people who feel that it is so much an intrusion on their privacy that they're going to bend the results in order to skate around it.
The consensus I'm hearing here is that this information, in the long form as well as the short form, is very important and that the question this comes down to is, how can you get accurate information without putting a threat in place that destroys the relationship of trust between government and its citizens?