Rf id is a means for the authorities, government, "the Man"...whatever you want to call it, to track all your activities by following your purchases. If there are no anonymous financial transactions, there can be no "underground". All things will be known, you can't buy marijuana, steroids, firearms, anything on the quiet...anything considered "contraband". They will try to do this by minting currency with Microscopic Rf id chips in the money that will have the serial numbers encoded. They will know who has given you money because the banks will be required to make the information available to..."the Man". Retailers, service providers will have the same requirements. If the chips are in the consumer products, they will know what you buy, and who sold it to you, how much you paid. If you go buy that ounce of marijuana one weekend, there will be an imbalance somewhere. Plus if they intercept a drug trafficker's money, they will know who gave it to them, because of the encoded serial numbers.
Really, it can be looked upon as a twenty first century version of the stamp act of 1765 where Britain wanted to track financial transactions, legal documents, permits, commercial contracts, newspapers, wills, pamphlets, and playing cards in the American colonies.