Hypothetically if you have someone who has a business and merchant service ability to swipe a card, then, they could make a sale and swipe the card. Let's assume it's for $10k. They incur merchant fees. The $10k gets credited to their bank, as revenue.

If the sale didn't work out, they could refund the $10k via a check, less any fees, and said check could be used by the cardholder however they want.

The business now has a debit too, so the net net is there is no tax to pay.

Like all MS this is fraught with risk, but it's certainly doable.