I can relate to people playing games with religious solicitors or salespeople trying to get you to buy crusty merchandise, as I do it myself; but I think it's pretty rude to do it to people with a legitimate reason to come calling. Those census numbers affect how tax dollars are allocated to your district. Some people don't answer their census and their community may see a little less funding as a result. Haha, that's funny.
If you answered the questions, but were just rude because the person disrupted you at home then you still get that government money allotment for your community (ie: the expected benefits back from your own tax dollars) but you made someones job miserable for a while. Bravo, good show.
My Dad's retired but does some City of Calgary census taking basically to kill time, and he encounters all sorts. Many don't answer the door, many don't return the numerous calls and door hangar notices; they think it's a waste of time. A lot of time's he'll encounter Muslim women who won't dare answer the door without a male family member present
. He'll explain to those who will listen in terms they can relate: Tax dollars are spent where the statistics justify that they are needed; if you don't wanna answer fine; but know where to complain if/when things don't happen in your neighborhood.