Is it really credible that Banksy would give the painting away with an embedded, remote-controlled, battery-operated shredder, that would activate 12 years later?
Banksy was also claimed to have been pictured this year after one of his work's appeared on the disused Scott Street Bridge in Hull. But perhaps the most improbable notion of all is that anyone truly feels that this most rote and replicated Bansky image is worth either a million dollars or a great deal of kerfuffle about its sensational destruction.
The statement added: "In case it was ever put up for auction".
Banksy is well known for his anti-establishment street art which often points a satirical finger at the world as it is today.
However, one owner did not pay heed to the warnings and destroyed the print he owned.
Another Banksy mural, depicting a workman chipping away at one of the stars on a European Union.More news: Princess Eugenie and Jack Brooksbank's wedding: How to watch in Canada
Graffiti's criminality is the reason for this mystery - but just who is Banksy?
In March 2005, he sneaked his own artworks into four of New York's most prominent museums, including the American Museum of Natural History, where he left a beetle with missiles on its wings in the 'Hall of Biodiversity'.
He held multiple exhibitions in the United Kingdom and USA throughout the 2000s and his profile rose after celebrities began snapping up his pieces.
The artwork was signed and dedicated and the vendor acquired it from the artist in 2006, the auction house said.
What do you make of Banksy's stunt? The 2010 documentary Exit Through the Gift Shop took a somewhat a jaundiced view of the booming street art scene at the time, which made global celebrities out of artists like himself and Fairey.
Active since the early 90s, there have been dozens of theories about Banksy's identity.
Some people are aware of who he is - associates and fellow artists - but have proven to be fiercely loyal to his wishes to stay a secret.More news: Sears may be days away from bankruptcy
Banksy has previously been named as Robin Gunningham - a former pupil at Bristol Cathedral School.
It has been suggested Gunningham could be Banksy, but another name through around is Robert Del Naja - better known as 3D from Massive Attack.
It is unclear whether this was part of a grand plan or whether the shredding was interrupted when alarmed auction house staff removed it from the wall.
The post, and reports of a man dressed in black sunglasses and a hat scuffling with security guards near the entrance to Sotheby's shortly after the incident, led to speculation the artist was present to trigger it.
"It's become worth more as a conceptual moment than as a work of art itself", Waterman told the Times.More news: Google Abandons Bid for $10B Pentagon Cloud Contract