In classic Banksy humor, the artist mocks authorities and the "vandal" characterization which is normally associated with street artists.

Street art is forbidden, and the people who do it are normally persecuted, for what is considered public and private violation of property.

Here the artist challenges the authority and makes the wall in which the stencil is placed an "official" graffiti area.

"Imagine a city where graffiti wasn’t illegal, a city where everybody could draw whatever they liked. Where every street was awash with a million colors and little phrases. Where standing at a bus stop was never boring. A city that felt like a party where everyone was invited, not just the estate agents and barons of big businesses. Imagine a city like that and stop leaning against the wall – it’s wet.”

Banksy cited in: Paul Gough, Banksy: The Bristol Legacy, Bristol 2010