I got counted twice at the last census.
You were supposed to report who lived in your household on April 1, 2000. We closed on our new house April 3, 2000 when I was 7 months pregnant with our first child. On the 1st of April we were still in our apartment, so I filled it out based on our apartment address.
We moved into our new house and after a while I get a knock at the door. A census worker tells me that they didn't get a census report for this address and they'd be happy to fill that out with me right now. I explain to him that the house was vacant on April 1st and I already filled out a census report based on where we were living on April 1st, we didn't close on the house until April 3rd. So he says okay and he goes away.
A few weeks later, a different census worker comes to tell me they need to fill out the census for our address. I explain all over again how we didn't own this house on the 1st, the people we bought it from moved to NC and I DID fill out a census form for our last address. She says okay and goes away.
A few weeks later, the first census guy comes back and says he talked to his supervisor and they told him to get the information from us from the census. By this time, I'd had my baby, so he counted my husband, myself and my baby (who wasn't even born until JUNE!)
So, I don't understand how people managed to NOT fill out the census form - they kept coming to the house until they got the information they wanted!