Is "Banksy on Advertising" Plagiarized?

It appears that the (kind of great) Banksy rant about advertising that's been going around lately is excerpted from his 2004 book Cut It Out and was actually written/inspired by Sean Tejaratchi circa 1999.

Here's a bit of Banksy's Piece from this year:

Fuck That. Any advert you see in a public space that gives you no choice whether you see it or not is yours to take, re-arrange and re-use. You can do whatever you like with it. Asking for permission is like asking to keep a rock someone just threw at your head. 

…And here's Sean's from his piece in Crap Hound magazine in 1999:

If I see an ad without asking to, it's images are mine to reprint and redistribute, with clearance neither granted nor requested. ..Why should I ask my assailant's permission to keep a rock he's just thrown at my head?

Sean writes about all of the similarities here – it hardly seems possible that this is a coincidence.

Update 3/14:  Sean just Tweeted "For the record: Crap Hound thanks appeared at the end of Banksy's book. Carelessness in layout years ago = Yes. Fraudulent? No. #banksy"