I don't like Matt Cutts. There, I said it. I don't trust him, one bit. I guess we're supposed to take what he says as gospel and quickly run around and make changes that he tells us to.
It's quite worrying though, as it suggests that js and CSS are ranking factors, or at least websites that Google "believe" are using questionable js or css, have or will be penalised?
I don't disallow js or css anyway, as Google knows exactly what they are, they're not web pages, so why index them or continue to crawl them.
Will we see some new ebooks tomorrow, "Turbo charge your rankings, SEO your CSS Files".