Stranger ask to borrow your phone? They may be a scammer looking to drain your cash.

Maybe, we should all just quit trying to be so darn friendly.

Too many scams, after all, are built around the notion that many of us want to play nice and believe that most people are good souls. If they say they need help, well, they probably need help. The hard truth is that scammers simply want to help themselves with our money.

"We want to believe the best about people," said Lisa Plaggemier, executive director of the National Cybersecurity Alliance, a nonprofit that raises awareness about fraud.

"When somebody comes to us with a little bit of a sob story, like 'Oh, can I borrow your phone? I lost my phone,' or whatever it is," Plaggemier said, "unless you're a security person like me, you're not immediately thinking of a potential scam."

And yet, here are two scenarios where our willingness to do the right thing could be exactly the wrong thing to do:

Why scammers want to borrow your phone

The "Can I borrow your phone?" scam: Maybe a 16-year-old approaches you at the mall, grocery store, or even an outdoor festival and wants to call Mom to get a ride home. Or maybe, someone's car broke down. Surely, nothing bad could happen, right? Wrong.

The phone in your purse or pocket isn't just a phone. It's often a digital wallet stuffed with apps that the crooks can use to steal hundreds or thousands of dollars. The crooks aren't dialing Mom; they're dialing for dollars.

"Really, what they're doing is getting into your peer-to-peer app and transferring your money out of the app into theirs," said Amy Nofziger, director of victim support for the AARP Fraud Watch Network.

The consumer ends up being vulnerable to what some cleverly call "virtual pickpocketing."

The stranger is able to stealthily hit the payment app on your phone, Nofziger said, and if you don't have it logged out, they're able to hit the "pay" button and easily transfer $150 or $200 or more to the crook's account. Your money is gone.

It looks like the stranger is making a phone call but they're putting in another number to transfer the cash.

Best bet: "Do not hand over your phone to strangers, as they could make financial transfers using your payment apps and accounts," according to an alert by the American Bankers Association Foundation.

You can offer to call a stranger's family member and keep that phone on speaker, instead of handing over a phone. Always make sure to log out of your cash transfer or payment apps and other financial apps after you're done.

Why a scammer 'accidentally' sends you cash

The "I accidentally sent you $300" scam: Maybe you get an email or message from someone who claims they made a typo and sent you money via Venmo or another payment app by accident. And the person asks: "Would you please send back my money quickly so I can pay my bills?"

Sort of seems reasonable. You don't want to keep money that isn't yours. Again, what could go wrong? Plenty.

Scammers are using "accidental deposits" or "misdirected payments" in a fairly elaborate scheme to steal cash. Some consumers have complained to the AARP Fraud Watch Network Helpline about such scams already, according to AARP's Nofziger. She recommends that consumers verify first by using a customer support contact that they have obtained on their own before automatically trusting anyone.

In late May, Michigan Attorney General Dana Nessel issued an alert to a "nationwide Venmo scam."

Criminals can try to scam you into sending them money via a payment app – or they can steal it directly.

As part of the accidental deposit scam, the crook will create a fake profile on a payment app like Zelle, Cash App, or Venmo, and tie a stolen credit card to it.

The crook then sends some cash to a random victim. The credit card company sees this as a payment to PayPal, which owns Venmo, not as a payment to an individual consumer, experts say, and it goes through to show extra cash in your account.

The problem is the random $200 or $300 that arrives in your account actually is stolen cash from a hacked credit card or bank account.

If you send any money back, ultimately the money you sent is just a transfer of cash from your account to the thief.

Not surprisingly, the thief is going to immediately withdraw whatever money you sent. And then, the crook will quickly close their Venmo or other peer-to-peer payment account.

Down the line, experts say, the credit card will discover the fraud and initiate a "charge back" against PayPal. The original transaction involving the stolen card is reversed but the victim has already paid the thief – and the victim isn't likely to get any money back.

Peer-to-peer transfers appear almost instantly. However, it takes more time for banks to catch scammers who are using stolen credit cards or bank accounts.

"People have to remember these things are like cash," Plaggemier said.

Nessel's advice: Never send back any money if someone says they've overpaid you for a purchase or made a typo when trying to move money via a cash app for another reason. Instead, contact the payment app first about the possible error.

Big money scams often grab the headlines

The accidental deposit scam isn't generating lots of buzz right now, but it's a scam that could build in the future. More often than not now, we're seeing reports where crooks steal tens of thousands of dollars at once, like with a tech scam or a romance scam.

Multimillion-dollar cryptocurrency investment scams are grabbing headlines, including one in May when two Chinese nationals were arrested by U.S. authorities on suspicion they laundering $73 million through shell companies tied to these elaborate investment schemes.

The schemes, which are dubbed "pig butchering," take several months to unfold. Scammers meet their victims on dating apps or even start a friendship after sending what seems to be an accidentally wrong number. (Ever get what seems like the wrong text, say to confirm a lunch or vet appointment? Don't answer it.)

The scammer gains your trust over time and might invest many months impersonating a friend or a love interest to ultimately encourage you to invest thousands of dollars in a cryptocurrency scam where you lose much or all of your life savings.

Verify first, before you trust someone

Increasingly, Plaggemier said, consumers must take more steps to protect themselves such as completing multifactor authentication to add an additional layer of security when signing into a payment app. Keep your computer software up to date with the latest security patches and updates. Use strong passwords that are at least 12 characters long and include letters, numbers and symbols.

The crooks know how to develop believable backstories, take advantage of human nature and, perhaps, our lack of knowledge on how things like payment apps work.

Venmo recommends that you contact its Customer Support service team directly if there's a questionable deposit. Don't engage with a scammer. You might even need to confirm first that a "friend" sent you cash, as Venmo notes "bad actors may attempt to replicate a profile picture to impersonate your friend on Venmo."

The American Bankers Association Foundation agrees and also advises that you contact the peer-to-peer service about the error. "If you send money back to the scammer, the peer-to-peer service could take funds out of your account or hold you responsible," the ABA Foundation's alert noted.

For the scam to work, the crook needs to create some story about a contrived emergency to convince you to move quickly while you might still believe the stranger's money has been transferred to your account.

It's best not to even engage with these alarming messages. Cybersecurity experts say the scammers in many cases can become increasingly aggressive with demands for you to return "their" money.

"They might call you names and tell you stories about how they are short on rent or have kids depending on them," according to the alert from the National Cybersecurity Alliance. "They might try to get you to call or text them so they can explain themselves."

Do not respond at all. Don't help a stranger get their hands on your money.

Contact personal finance columnist Susan Tompor: stompor@freepress.com. Follow her on X (Twitter) @tompor.

This article originally appeared on Detroit Free Press: Avoid this scam by never letting a stranger borrow your phone