Why on earth would there be such a law?
Well I ask because I've read some pieces saying that more and more business are doing away with cash registers, checkout counters, etc and modeling themselves after places like the Apple Store. J.C. Penney announced last summer an overhaul of their system of payment to go toward mobile checkout and self-checkout systems.
I just wonder if we are moving toward an age where cash is no longer relevant. To me it's scary that we could one day find ourselves where the only claim we have to our money is a figure on a computer screen.