Graphic showing cell phones and wallets to represent P2P payments

Ben Bernard got dumped on Venmo, for all the world to see.

The Boston-based digital marketer went out for a second time with a man he'd met online. The two had agreed to split the bill, and Bernard paid for dinner with his credit card. Afterward, his date texted Bernard his share via Venmo, the peer-to-peer electronic payment service. (Find out how Venmo did in CR's review of mobile P2P payment services.)

The date also added two emojis to his text: A hand making a peace sign, and the word "END." 

Friends saw the text on Venmo's public text feed. "They sent me screen shots of it and said, 'What was that about?' " Bernard recalls.

"It was an awkward way to tell me we were breaking up," he adds. "It felt like when one of Carrie Bradshaw's boyfriends on 'Sex and the City' breaks up with her using a Post-it note." 

The New P2P Etiquette

Mobile peer-to-peer payment services have revolutionized how consumers pay each other for shared meals, rent, group gifts, and countless other financial transactions. If you're buying concert tickets for a group, your friends can pay you their share electronically—and instantly—with an app from Apple Pay, Square's Cash App, Venmo, Zelle, or a similar service. With a few taps on a smartphone screen, the money heads toward your P2P account or debit card.

More on P2P

But P2P also has the potential to cause friction among family, friends, love interests, and colleagues. While it's easy to make electronic payments—and to ask for them—it's not so easy to discern the new rules of engagement.

"These apps enable transactions to happen without life getting in the way," notes Thomas P. Farley, a New York-based etiquette expert also known as Mister Manners. "But as we embrace the technology, it’s important to have a set of standards so etiquette is not forgotten."

Here are a few guidelines to prevent the disruption of your relationships in the world of P2P payments, and to know what to tolerate from others.

Don't Ask for Every Little Cent

Apps like Splitwise let users split bills to the penny, and P2P services make it a snap to request and pay small sums, down to the penny.

That can make things fair but not fun. Asking for $50.03 back instead of an even $50 was annoying in the past and it's still annoying now, Farley says. 

"We’re not walking Excel spreadsheets," he says. 

Indeed, a study recently published in the Journal of Experimental Psychology: General by researchers from the graduate business schools at Harvard and the University of Virginia found that people who are involved in petty P2P exchanges—say, asking for reimbursement of $8.17 vs. $8—aren't liked as much as people who round up or down. Even with money gifts, recipients dislike petty exchanges—say, giving $5.15 instead of $5, the researchers noted. 

"Engaging in precise payments makes relationships feel more transactional, like dealing a bank teller," says Tami Kim, an assistant professor of marketing at the Darden School of Business at the University of Virginia, one of the study's authors.

Translation: People prefer when you round up or down. 

Treat and Be Treated

A potential casualty of the P2P culture is treating others. Now that it's so easy to pay back small sums, why not reimburse your colleague who spotted you a couple of bucks for coffee? Or even ask for that money back.

"I do have those friends who will send me a Venmo request for that $3 that I owe them," says Bernard. "It makes it easier for them to get what they owe because they can make the request a few hours later when they’re a little more distant." 

The risk of those kinds of interactions, says Farley, is a loss of the back and forth that builds and strengthens friendships. If you want to pay someone back for doing you a solid, do so by spotting them  another time, he advises.

Be Prepared to Pay Up

P2P payments have done a major service to dining partners the world over: They expose the shirkers. Now that everyone at the table gets a text with their share of the tab, you can't suddenly leave for the men's room and return to find your portion covered.

"There are fewer places for people to hide," Farley states. "If you're in a situation where you don’t have the money, you shouldn’t be participating."

On the flip side, ask promptly for remuneration, before the event in question is forgotten. 

"People get annoyed that they get a random request they didn’t expect," says Ashley Carman, a New York-based tech writer whose podcast, “Why’d You Push That Button?,” has included a segment on Venmo.

Make Your Transactions Private

As Bernard discovered, Venmo has gained popularity—and notoriety—for its unique feature of making users' financial transactions public by default.

Public transactions can be viewed not only by people you know but also by anyone who uses the platform. Monetary amounts aren't disclosed, but the world can see who you paid, when you paid, and often—when you add emojis or words—what you paid for.

To prevent your Venmo transactions from being perused by friends, exes, and strangers alike, make them private, Farley advises.

"Don’t be showing off who you’re paying and what you’re paying him for," he says. "And if you’re doing it to embarrass someone, that’s even worse. Let this be a private matter."

Christina Tetreault, senior staff attorney for Consumers Union, the advocacy division of Consumer Reports, goes further: Make all your P2P settings the most private possible to ensure the least sharing of your personal data, she says.

Among five mobile P2P services CR recently tested, only Apple Pay made those settings the default, a major reason it ranked at the top of our ratings. But, Tetreault notes, with the other P2P services we tested, it takes only a few seconds to opt for more private and secure settings. "Taking these steps may help you avoid headaches and heartaches," she says.

Don't Leave Home Without Cash

Digital payments may have made major inroads in the U.S., but we're not like Sweden yet, where 80 percent of transactions are cashless.

Farley worries that without cash, certain transactions that make up polite society won't happen as often.

"You’re not going to want to Venmo the bellhop or the housekeeper in the hotel," he says. "We’re nowhere near being a cashless society, so don't become so reliant on P2P that you’re skimping on tips or have to be covered by the person who’s been responsible enough to bring cash." 

Carman, the tech journalist, says she still follows the rule that her parents taught her: Always have on hand at least $20 in cash for emergencies. 

But it's not a habit shared by her peers.

"I probably have lost a lot of money because I don’t use Venmo," Carman adds. "I’ll say, 'Hit me back with some cash when you have it.' But none of my friends carry cash."

Peer-to-Peer Payment Apps

Technology allows for easy payment of goods and services—but, if you're not careful, peer-to-peer payment apps could end up costing you. Consumer Reports expert, Octavio Blanco, shows 'Consumer 101' TV show host, Jack Rico, how consumers can protect themselves when using peer-to-peer payment apps.