For the last two weeks, Ivy Leaguers have lined up by the hundreds around lunchtime, plastic in hand, for cured salmon tartines, shrimp tempuras and mint chocolate tahina shakes at the newly renovated and rechristened Franklin's Table food hall across from the University of Pennsylvania.
It's hard to spend any Benjamins at Franklin's Table. Four of the five lunch spots won't take cash.
Goldie, High Street Provisions, DK Sushi and KQ Burger have all ditched paper currency in favor of credit and debit cards to simplify purchases and speed up lines.
Testing out new approaches to payment at universities is ideal, says Goldie partner Steve Cook, because "students have less experience with cash and more [with] noncash forms of payment."
Nationally, Starbucks and Amazon are experimenting with cashless in-store shopping, while Chicago's City Council is considering an ordinance to ban the practice altogether, contending that it excludes people who cannot afford them.
At Goldie, where queues for falafel can stretch the food hall's width, not accepting paper money, though slightly more costly for the restaurant, saves the "headache" of not having to count and distribute cash, said Cook. The Goldie booth at the Pennsylvania Avenue Whole Foods is also cashless.
A malfunctioning payment tablet was enough to briefly stop business on opening day for the High Street spin-off High Street Provisions. Still, being cashless helps make the "steps of service as lean as they possibly can [be]," said founder Ellen Yin. She wants her food ready within four minutes of ordering.
Ninety-five percent of diners at her Fork restaurant pay by credit card, she said. At High Street on Market, just a fourth of customers still pay in cash.
At the hall, only Pitruco Pizza, and branches of Little Baby's Ice Cream and the Juice Merchant, will take paper money or coins.
Little Baby's co-owner Peter Angevine says the credit card processing fees don't make sense, considering that his smallest scoop goes for $3. But also, he says, "Not everybody should need a credit card to buy ice cream." Without lunch offerings, the ice cream shop can accommodate a slower checkout.
Only a handful of people have been turned away because they had only bills, according to proprietors of the cashless businesses. Also card-only in the city are four Sweetgreen salad bars and an outpost of the Australian-style coffee shop Bluestone Lane.
There are other payoffs for merchants: Cashless payments also make calculating taxes, payroll and inventory numbers easier, and provide valuable customer data.
With the proliferation of such services as Venmo, ApplePay and Square, some companies are eager to proclaim the death of cash.
"Empirically, it's not happening," said Bill Maurer, a University of California-Irvine anthropologist who studies currency. "We've seen this before." For instance, in 1963, Diners Club, the first credit card company, launched an experiment, asking the citizens of Winsted, Conn., to use plastic-payment only for just one day. "Cash died today," the city's paper declared.
On Wednesday, Visa announced that five Philadelphia-area small businesses had won $10,000 to improve their cash-free payment technology. One winner, Really Reel Ginger at Reading Terminal Market, recently switched from Square's headphone-jack card reader for phones to a free-standing point-of-service tablet from the company Clover.
"People were kind of funny about you taking their card to swipe it on your telephone," said Iliyaas Muhammad, 36, who runs the business with his wife, Hadia, 33.
Maurer added that it's not uncommon for new payments to be tested out at universities and theme parks, where there are "lots of customers in a contained space."
He cautioned, however, that "anytime you start putting restrictions on payment, you start shutting people out, and can create new forms of hierarchy."
Businesses' going cashless would hurt the 7 percent of Americans who often have neither credit nor debit cards, according to 2015 FDIC data.
Mindful of that economic divide, Massachusetts has required all businesses to take cash since 1978.
While Franklin's Table is usually packed, several Penn students who described themselves as low income said the restaurants in the food hall are not as affordable as the previous tenants at Moravian Food Court, which included Taco Bell and Pizza Hut. At Penn, about half of students are expected to pay the estimated $73,000 cost of attendance without financial aid.
"We already have Sweetgreen on campus, where salads are $10," said Lyndsi Burcham, 21, a first-generation student from Kansas City. As a freshman, she used to go to the old food court regularly.
Some students just miss their favorite lunch spot.