Here in Australia we have very similar rules and civil disobedience. I have always evaded the census. We're told no link to individuals is kept and the info is 'destroyed'. I take the word 'destroyed' to be some kind of public service double speak after discovering all the census forms for Adelaide (1984) bundled up at Adelaide international airport ready for shipment to an address in Virginia USA.
In times past I insisted on the option of mailing the form in. I took steps to leave no finger prints or DNA on the form and removed identifying numbers penciled on the back. Some time later a letter came warning me over my apparent failure to submit a census form. I wrote back that I had complied fully and never heard from them again.
It used to be you just had to say you were overseas on census night.
unclebruce who was in a siberian village one census night and in deepest darkest ireland on another.