I'm not sure if anyone else would be interested but here's how I handled the census this year -- pretty much the same as I have every decade since 1970. I gave the number of people living in our house (2) and scrawled a big N/A after every other question. My reasoning is this. The Constitution does call for a census for the purpose of reapportioning legislatures. All they need for that is raw numbers. Age and gender don't matter, nor does whether one is registered to vote, because districts are apportioned based on sheer population, not the number of registered voters. On the questions regarding race and ethnicity I not only scrawled N/A but "very offensive."
The only time I ever heard from anybody regarding my choices as to what information to reveal was in 1970, when somebody called from the Census Bureau to try to talk me into disclosing more. I was watching a Lakers game and they were not winning, so I was in no mood to be messed with. I went through my argument that a constitutional census would ask only for sheer numbers, and that there was no constitutional warrant for them to know more -- I'm pretty sure I also said something about being offended at the census being used as tax-funded marketing research for corporations, which should spend their own money to acquire such data. When the poor girl asked whether it wouldn't be relevantwhether I was registered to vote or not I came back with the sheer numbers argument. Finally she gave up and that was the last I ever heard from the census people.