According to the National Governors Association (NGA), failure to collect sales tax on online sales results in annual tax revenue losses of at least $35 billion. State governments are unable to apply sales tax rates to most Internet orders for out-of-state goods and services, but this has not stopped them from trying to do so after the fact. Twenty state income tax forms now have a line on which taxpayers are supposed to report sales taxes owed on out-of-state purchases. To get people to report out-of-state purchases, states threaten audits that would uncover credit card records. Why do you suppose that most states with lines on tax forms that require taxpayers to report taxes due on out-of-state purchases do not audit every taxpayer who chooses to leave the line blank?