Yes, we know. And they have Ministry sanction to hunt down anyone they're aware of who hasn't registered. [Scorpius doesn't like either option, but this one seems the most manageable.]

They have the Trace on so many people, so long as you don't give them a reason to look into you, they won't bother to. As far as they're concerned, they've won. They have no reason to worry. Better to let them keep thinking that.