LuciferSum  

I thought you might enjoy this (real) announcement from the Banksy Forum last night:

' BANKSY AUTHENTICATION
Important information about Banksy Authentication and Pest Control -
Pest Control is the organisation that verifies items created by Banksy.
We catalogue the artists work and hold the only existing records of commercial sales, as well as a comprehensive library of photographs of Banksy's images dating back to inception. All works authenticated by Pest Control have been done so in conjunction with the artist.
Banksy does not provide this service through any other third parties and we would caution collectors against relying on such bodies.
Pest Control does not authenticate street pieces because Banksy prefers street work to remain in situ and building owners tend to become irate when their doors go missing because of a stencil.
Banksy has a casual attitude to copyright and encourages the reproduction of his work for your own personal amusement, so it's with regret that he finds himself having to deem pieces either 'real' or 'fake'. He would encourage anyone wanting to purchase one of his images to do so with extreme caution, but does point out that many copies are superior in quality to the originals. Since the creation of Pest Control in January 2008 we have identified 89 street pieces and 137 screen prints falsely attributed to the artist.
Due to the fact many Banksy pieces are created in an advanced state of intoxication the authentication process can be lengthy and challenging. We ask for your patience when using this service.'