They start with "random" checks. They ask innocent questions. In a few years, after residents are used to the intrusion, they move up to their real purpose. Are you a gun owner? Are you harboring any conservatives?
You have the right to shut up, to keep your opinion to yourself.
Or "Do you belong to a hate group?" And yes, they will consider TRUE Christianity (not the Christianity that comes money-grubbing televangelists who are motivated by the almighty dollar) to be a hate group.