The rumour mill has been working overtime ever since a mystery man visited Ogden, Utah, and left three enormous tips for serving staff - including $5,000 on a $214 bill. He left tips totalling $7,000 around August 17.
And rumour has it that the mystery man was Richard Branson.
The tipsOgden is a small town near Salt Lake City, where this sort of thing is unheard-of. The three tips have created an enormous amount of debate, but very few hard facts have emerged.
It was originally reported by the Standard Examiner, which said: "Although no one was willing to identify the generous gentleman, Allen [one of the servers who benefited from the tip] guesses both tips were courtesy of the same person". The Salt Lake Tribune highlighted that both men used an American Express card.
The Daily Mail has suggested the mystery man could be Branson, citing 'multiple sources' who have apparently confirmed that he was in town. The newspaper suggested he could have been there as part of the Summit Series, an annual conference for entrepreneurs which has a base just outside the town.
We can only guess at who left the tips and why. However, the mystery man is far from the only one leaving unusual tips. Here are five of our recent favourites.
Unusual tipsIn July, Bob Erb, a lottery winner from British Columbia, stopped for a burger and fries on a road trip and got chatting with the restaurant owner. After hearing that the owner's 25-year-old daughter was recently diagnosed with cancer, he left £10,000 and told the owner to keep the change.
That same month Colleen Gallagher, a cocktail waitress from Chicago, received a £11,000 tip from a businessman after sharing her troubles. John Boc, the CEO of an investment company, gave her the tip after she told him she was struggling financially. He told her to take the money from his credit card, saying: "Life's too short to be feeling blue."
In May, a Tumblr user posted a picture of a $1,000 tip her mother had been given by a stranger, after she had mentioned to him that she'd love to travel to Italy. Next to the amount he had written 'Your ticket to Italy. Enjoy!!'
A week earlier, CeCe Bruce, a Steak 'n' Shake waitress in Indianapolis, was given a $400 tip by a regular customer. She had seen the waitress dealing with a table of difficult customers, and left the tip in recognition of how she had handled it.
And then there's Seth Collins, who is travelling the US in a bid to leave $500 tips for waiting staff in all 50 states. It was his brother's last wish that Seth leave a $500 tip to honour his brother's life, and after he posted a video online of the first tip he gave, donations came flooding in - and he received enough to carry out this unusual road trip.