Cash is not just going out of style, it's already gone in some places.

Aaron Graves and her fiancé discovered that at one of the last Twins games of the year. They left their credit cards in the car, figuring they could just use cash at the stadium.

They were wrong.

The couple were among the fans turned away at concessions stands and redirected to a sleek white kiosk — one of five so-called reverse ATMs around Target Field. The sign on the machines says, "Convert cash to card."

"It's odd to me," said Graves after the couple inserted cash into the machine and got a pre-paid debit card. "You would think you could use cash anywhere."

Many airlines stopped accepting cash years ago at check-in counters and on flights. In the pandemic, sports stadiums, amusement parks and restaurants moved to cashless transactions as a way to limit contact, make do with fewer workers and to be more efficient.

The share of payments made with cash went from 26% in 2019 to 19% in 2020, according to an annual consumer survey by the Federal Reserve. It ticked up slightly last year to 20%.

The Salvation Army, which encourages people to toss dollars and coins into its red kettles around the holidays, has added QR codes in recent years for donors to make digital payments.

All the major sports venues in the Twin Cities have stopped accepting cash — Target Field, Target Center, U.S. Bank Stadium, Xcel Energy Center and Allianz Field. So has Valleyfair.

Some high schools have also stopped accepting cash to attend games and moved to online ticketing systems.

As more businesses go cashless, some consumer advocates are concerned that people who don't use credit cards, smartphones or even banks will be shut out. An estimated 5.4% of Americans didn't have a checking or savings account in 2019.

"That's a potential concern," said Ted Rossman, senior industry analyst with Bankrate.com. "Although to be fair, it's maybe a bit of a self-selecting audience [going to a sport arena or concert hall] because chances are to get into that venue in the first place you may have had to buy a ticket with a credit or debit card."

Before the pandemic, some elected officials became alarmed by the shift toward cashless. Lawmakers in New York City, Philadelphia and San Francisco passed measures that required businesses to accept cash. But the momentum for those kinds of laws seems to have slowed since the pandemic.

Companies like Ready Credit, based in Eden Prairie, offer businesses a way to go cashless while still abiding by laws where they exist. The firm, which has about 45 employees, now has its machines in about 80 sports stadiums, 60 amusement parks and 110 airports.

In the Twin Cities, they can be found at Minneapolis-St. Paul International Airport, Valleyfair and Target Field.

"We get a significant number of inbound inquiries every day about cashless," said Ready Credit CEO Brian Hedberg, who added that going cashless can help businesses find cost savings and become more profitable.

Since 2019, Ready Credit has tripled the number of kiosks it has deployed — to more than 1,100. Now it's looking to grow more globally while also piloting its kiosks in movie theaters and hotels that are also moving toward cashless operations.

In addition to not having to fumble with bills and coins, experts say there are other costs associated with cash such as theft — either by outside criminals or by employees — as well as counting cash, armored car fees and trips to the bank.

"Handling cash can be expensive," Bankrate's Rossman said.

For credit cards, businesses pay swipe fees of around 2% of a purchase total. But, Rossman noted, data shows that people also spend more money when they use credit cards.

Concerns that initially arose in the pandemic about the safety of handling cash have mostly subsided. But many venue operators say they're not planning to go back to accepting cash.

"Now that we're there, it's kind of hard to dial that back," said Matt Hoy, the Twins' senior vice president of operations.

A handful of stadiums around the U.S. had begun to go cashless before the pandemic. Hoy was initially skeptical of the concept, saying he didn't think fans would want to pass their credit cards down a row to a hawker.

But then the pandemic came along and venues everywhere were looking for ways to enhance safety and minimize touchpoints to make people feel more comfortable. At the same time, many also rolled out mobile ordering through smartphone apps.

"Cash used to be king, but COVID changed all of that for consumers who worried about germs and dirty bills," said Melissa Ferlaak, a spokeswoman for Valleyfair. "So we really saw a strong benefit to going cashless."

She added that it's also helped the park speed things up at concession stands so customers spend less time in lines.

Xcel Energy Center in St. Paul began moving toward cashless operations in 2019 when it first rolled out its mobile ordering system aimed at reducing wait times. It fully converted in fall 2020, said Kelly McGrath, a spokeswoman for the arena.

Instead of cash-to-card kiosks, the arena has a guest services counter where employees can help people put cash onto an online account in the mobile ordering app.

McGrath added that the venue doesn't see many people who do so.

"We certainly operate it as a service because we don't want that to prohibit someone from having an enjoyable experience here, but the vast majority of people either have Apple Pay or a credit card payment as an option," she said.

Representatives of Target Center, U.S. Bank Stadium and Allianz Field confirmed they do not have reverse ATMs on-site and did not specify any other accommodations for people who arrive with only cash.

Ready Credit, which first launched in 2005, initially put its machines in retail stores to offer a quicker way for consumers who primarily use cash to get a prepaid debit card.

Its kiosks first appeared in 2017 at Minneapolis-St. Paul International Airport, where there are now four of them. In 2018, there were about 18,000 transactions on those machines, according to airport spokesperson Jeff Lea.

There is a $6 fee to use the cash-to-card kiosks in airports. But there's no fee at stadiums or amusement parks where the operators of those venues pay Ready Credit, Hedberg said.

Hedberg added that the kiosks have a broader appeal beyond just those who don't have credit or debit cards. Some people just prefer to use cash. And parents may not want to hand over their credit card to a child they're dropping off at an amusement park.

At a recent Twins game, some of those who found themselves at the reverse ATM didn't have a payment card. Others, like Darnell Gray, had a debit card, but didn't want to use it.

"I have to pay some bills, unfortunately, so I can't use that card," said Gray, who was using the machine so he could buy tickets to attend a game the next day.

He's a bartender at the stadium and not a big fan of the cashless environment. Every game, somebody tries to buy drinks from him with cash.

"All the time," Gray said. "I send them to these."