I seem to recall that there was an “outreach” program here in CA to get the “undercounted” (read: illegal) minorities accounted for in the 2000 census. They made a big deal out of the anonymity, and that the census workers weren’t to report immigration status.
You recall exactly right. Actually, there were a couple of legal challenges to the census trying to substitute models for a real count on the ground that the models were more accurate than the real thing!