A real nightmare occurs when a large number of businesses don't accept cash. As this process proceeds, people who are unbanked or can't get a credit care are now not only locked out of the financial system, but also the monetary system! It hugely centralizes the management of the entire consumer economy in the hands of a few bankers who have no responsibility to the electorate - and there's no escape valve.
I would see this practice immediately banned. If a note is legal tender for all debts public and private, it is an attack on the monetary system to not accept it. I can understand why individual businesses would rather not deal in cash, but we can't allow their narrow interests to dominate the public interest.
EDIT: It does make sense to not accept notes for large transactions (e.g. more than a few hundred dollars), but it's crazy to not be able to buy toilet paper.