Then I'm curious about these questions:
1. Is this the most cost efficient method to deal with it? It seems a bit silly, to me, as this is a game of cat and mouse, and those tend to be very expensive in the long run, if you want to win.
2. Would it be worth investing in a digital solution such that a bill could be copied, but only one copy of that bill can ever be recirculated, so you could "back up" your money, digitally, then re-print it somewhere else, but you could never spend it more than once, as a general solution to counterfeiting?
3. Would either of these actually save more money than just ignoring the problem?
4. 100% digital? Maybe not online as a requirement, but definitely tap your card to transfer funds to someone? Why do we still have paper bills anyway, with multiple demonstrated cryptographic protocols that could replace them entirely?