~GeeS~
First off, that isn't a script but a meta tag.
Any successful searches you found are the result of HFS users that don't know how to protect their site properly. Who knows, maybe they want their sites indexed to begin with. (I could actually care less how they run their sites). My objective here is to inform the people who weren't aware of this and who might find this information helpful.
What I showed you above is supposed to stop "all" search engines from indexing a site.