The Census is starting up again, and the Better Business Bureau wants to remind people to use reason and caution when answering the door. You’re required by law to answer Census questions, but scammers may pose as legit Census workers and take advantage of the situation. “Law enforcement in several states have issued warnings that scammers are already posing as Census Bureau employees and knocking on doors asking for donations and Social Security numbers.” Here’s how to identify a real U.S. Census worker.