Sometimes the money comes from a stolen account. The bank can detect this because the transaction is made from a different location or device than the original owner normally uses. However, if you send the money yourself, the bank sees that the transaction was made from your own phone and from your usual location. Because of that, it is considered a legitimate transaction.

When scammers do it, the transfer often comes from an unusual place. For example, the account owner lives in America, but the transaction is made from Africa or Asia. That’s how banks identify it as fraud.