DaveN hints at the technique today.
If you want to see exactly what sorts of spamming he’s talking about with other sites search pages, some simple Google searches will show you. (You’ll always need to show omitted results when manually typing in these searches.)
Of course, I tend to trust what DaveN puts out… if he says this is working then I’m sure it’s having some effect. That said, it’s gotta be a hole that Google can plug pretty easily. Unless this is a case where search engine engineers are blind to detecting what a search engine result page looks like. ;)