What happens to someone who has never paid taxes?

Your house, your car and your children will got repossessed until you have paid back your debt.

While the above is one possible answer, pros in the field constantly find that generally people who don't understand enough and think they are NOT paying taxes when they should have, are so foolish in reality they have paid lots of taxes they would have refunded, and had other benefits, had they filed returns. That happens because the person generally either made such a small amount (and with deductions/exemptions, etc., expenses) they had no tax payment liability anyway and would have in fact gotten credits provided to them. Or they were indeed working and earning and there already was tax, waay too much (considering exemptions/deductions/expenses, etc) deducted from their pay, they just don't understand how the process works.