Serina Wolfe, 24, from Buffalo, New York, dined at the Clear Sky Beachside Cafe in Florida on June 27, where she spent 55.37 USD on food.
Before she left, she added a 5,000 USD (around 7,100 AUD) tip which she charged to a credit card.
At first, the generous tip attracted praise online after the waitress, who had had a difficult week following the death of her dog, shared the story of the 'Good Samaritan'.
Now, it's alleged Wolfe was actually using her boyfriend Michael Crane's credit card, and may have given the tip as revenge for him refusing to buy her a plane ticket back to New York.
According to an affidavit, the couple had rowed over the plane ticket and Michael had put a stop on his credit card.
But he'd removed the block before Wolfe visited the restaurant.
Crane reported the $5,000 charge to his credit company as fraudulent after Wolfe allegedly denied leaving the tip.
He told police he thought Wolfe was either drunk or 'trying to get back' at him according to her arrest affidavit.
Wolfe has been charged with grand theft.
It's unclear whether the waitress, who had already been paid the tip, will be forced to return the money.