On the case of Satriani vs Coldplay (i.e. the true genesis of "Viva La Vida"?)

http://www.youtube.com/watch?v=1ofFw9DKu_I

I've heard that Satriani's bringing suit against them. On the surface, it would seem logical: the two melodies and their underlying harmony are eerily similar.

It's another thing entirely to define a clear causative relationship, though. If Coldplay could reasonably prove that they hadn't heard that song previously, I'd be willing to believe them. The timing of release between Satriani's version and any substantive earlier recordings from Coldplay would be critical to evaluate, too.

I'd also expect a certain amount of musical integrity to come from Coldplay, too. If Chris Martin or whoever had heard that album prior to composing the song, I think it would be reasonable to offer some form of financial tribute to Satriani to account for the likelihood of that song having imprinted itself sonically (even if subconsciously) into Martin's brain.

I'd also like to hear about Satriani's genesis for his own composition. Is it not possible that both of them had heard a traditional Spanish melody somewhere and each interpreted it separately, but also quite similarly?