One of the silliest questions in the Census is in two parts:-
What job do you do? (Husband "School Cleaner")
Describe what this job involves. (Husband "Eh?")
He was tempted to reply "Robbing banks then cleaning their toilets".
Your ethnicity? He was tempted to answer "Senoufo" but thought they might not have heard of this tribe.
It must be tempting for people to answer facetiously to these daft questions, but I suppose they'd risk a fine.