We have always had the cheaters.
The only things I buy new is food, medicine and stuff like soap and toilet paper. :)
TOUCHE!!
That's why you'll always need someone to catch the cheaters. You may eliminate the need to prepare a tax return subject to IRS scrutiny but some agency (federal, state or both) will still need to determine taxable versus nontaxable transactions and the accuracy of each. This will not happen automatically without the threat of punishment for non-compliance.