Burke, a stalwart of Chicago politics who was first elected to the city's Board of Aldermen in 1969, has introduced an ordinance that would prohibit restaurants and retail outlets from refusing to accept cash. Federal reserve notes, Burke explained to Chicago's NBC affiliate, are "legal tender for all debts public or private. So follow the law."
If it were actually the law that businesses have to accept cash, of course, there would be no need for Burke's ordinance, which threatens businesses with $2,500 daily fines and revocation of their business licenses.
For the record, the U.S. Department of the Treasury's website says that "private businesses are free to develop their own policies on whether or not to accept cash." The City of Chicago itself requires residents to pay with credit cards, checks, or money orders for booted vehicles. The city's buses don't accept half-dollar coins, which were legal tender the last time I checked.
"Legal tender for all debts" means just that: if you owe someone for services or goods **already provided**, they cannot refuse to accept cash. But if you haven't bought the goods or services yet, they can decline to accept any form of payment they wish.
But if you're in a restaurant and they bring you the check at the end of the meal, cash would qualify as legal tender for services or goods they've already provided.
I'm sure they have "no cash" signs all over the place and make sure the customers know that, but it could still lead to a hilarious confrontation. "Take my money!" ;)
Last year my eye doctor instituted a policy of no cash. It is noted only on a sign posted at the checkout counter, which you get to only after the examination. So you find out after the exam or treatment has been given. Not a problem for me as I have no co-pay. I note that my dentist asks payment at the start of visit, having calculated the costs ahead of time for whatever service is rendered. But cash is acceptable to him.