I do not agree that one has to accept FRNs for payment, if that was true, then our demands for lawful money would hold no legal standing. The demand for lawful money, is, in fact, a refusal of FRNs.
"There is, however, no Federal statute mandating that a private business, a person or an organization must accept currency or coins as for payment for goods and/or services. Private businesses are free to develop their own policies on whether or not to accept cash unless there is a State law which says otherwise." http://www.treasury.gov/resource-cen...al-tender.aspx
I always demand lawful money and when I pay in cash, I tell the other party I am using lawful money to pay. Simply putting up a NOTICE in any Corporation:
"Only Lawful money accepted for payments" will suffice. There is no law that requires one to accept FRNs as payment, there are court cases that denote US Bank notes must be accepted, but never have I seen one that rules FRNs must be accepted.