There are a small number of restaurants in my area where they do not accept cash for payment. They only accept electronic payments such as credit cards, local debit cards etc.
Is this legal? On most currencies, it is written on the note something along the lines of "this note settles X dollars of debt". If a customer offers to purchase a product or settle the bill for a service they have consumed (e.g. food already eaten, gas already pumped into the car) via cash, can the seller deny it?
On a related topic, must business entities accept cash for invoice settlements? I know that the party receiving the payment can charge a "reasonable fee" for processing the cash (e.g. thousands of coins). Can they, for example, demand the debt be settled by bank transfer only?