What he was trying to say is that no one is "counted." No one is "no longer counted," people are asked in the survey what their current status is, and they in turn represent hundreds of others to compile the national figures.
Whats to keep them from lying?
Nothing. But there's no reason for them to lie either. It's not really an issue. Why do you think it would be?
shame, embarassment nothing to gain from giving the facts.